diff --git a/lib/webrick/cgi.rb b/lib/webrick/cgi.rb
index f22480b8..c86d36c9 100644
--- a/lib/webrick/cgi.rb
+++ b/lib/webrick/cgi.rb
@@ -160,7 +160,7 @@ def service(req, res)
         __send__(method_name, req, res)
       else
         raise HTTPStatus::MethodNotAllowed,
-              "unsupported method `#{req.request_method}'."
+              "unsupported method '#{req.request_method}'."
       end
     end
 
diff --git a/lib/webrick/httpproxy.rb b/lib/webrick/httpproxy.rb
index 196682ec..189faa9b 100644
--- a/lib/webrick/httpproxy.rb
+++ b/lib/webrick/httpproxy.rb
@@ -118,7 +118,7 @@ def proxy_service(req, res)
         public_send("do_#{req.request_method}", req, res)
       rescue NoMethodError
         raise HTTPStatus::MethodNotAllowed,
-          "unsupported method `#{req.request_method}'."
+          "unsupported method '#{req.request_method}'."
       rescue => err
         logger.debug("#{err.class}: #{err.message}")
         raise HTTPStatus::ServiceUnavailable, err.message
@@ -149,7 +149,7 @@ def do_CONNECT(req, res)
       end
 
       begin
-        @logger.debug("CONNECT: upstream proxy is `#{host}:#{port}'.")
+        @logger.debug("CONNECT: upstream proxy is '#{host}:#{port}'.")
         os = TCPSocket.new(host, port)     # origin server
 
         if proxy
@@ -175,7 +175,7 @@ def do_CONNECT(req, res)
         @logger.debug("CONNECT #{host}:#{port}: succeeded")
         res.status = HTTPStatus::RC_OK
       rescue => ex
-        @logger.debug("CONNECT #{host}:#{port}: failed `#{ex.message}'")
+        @logger.debug("CONNECT #{host}:#{port}: failed '#{ex.message}'")
         res.set_error(ex)
         raise HTTPStatus::EOFError
       ensure
@@ -241,7 +241,7 @@ def choose_header(src, dst)
         if HopByHop.member?(key)          || # RFC2616: 13.5.1
            connections.member?(key)       || # RFC2616: 14.10
            ShouldNotTransfer.member?(key)    # pragmatics
-          @logger.debug("choose_header: `#{key}: #{value}'")
+          @logger.debug("choose_header: '#{key}: #{value}'")
           next
         end
         dst[key] = value
diff --git a/lib/webrick/httprequest.rb b/lib/webrick/httprequest.rb
index 2b50037e..7f9c002f 100644
--- a/lib/webrick/httprequest.rb
+++ b/lib/webrick/httprequest.rb
@@ -224,7 +224,7 @@ def parse(socket=nil)
         @script_name = ""
         @path_info = @path.dup
       rescue
-        raise HTTPStatus::BadRequest, "bad URI `#{@unparsed_uri}'."
+        raise HTTPStatus::BadRequest, "bad URI '#{@unparsed_uri}'."
       end
 
       if /\Aclose\z/io =~ self["connection"]
@@ -464,7 +464,7 @@ def read_request_line(socket)
         @http_version   = HTTPVersion.new($3 ? $3 : "0.9")
       else
         rl = @request_line.sub(/\x0d?\x0a\z/o, '')
-        raise HTTPStatus::BadRequest, "bad Request-Line `#{rl}'."
+        raise HTTPStatus::BadRequest, "bad Request-Line '#{rl}'."
       end
     end
 
@@ -563,7 +563,7 @@ def read_chunk_size(socket)
         chunk_ext = $2
         [ chunk_size, chunk_ext ]
       else
-        raise HTTPStatus::BadRequest, "bad chunk `#{line}'."
+        raise HTTPStatus::BadRequest, "bad chunk '#{line}'."
       end
     end
 
@@ -581,7 +581,7 @@ def read_chunked(socket, block)
 
         line = read_line(socket)              # skip CRLF
         unless line == "\r\n"
-          raise HTTPStatus::BadRequest, "extra data after chunk `#{line}'."
+          raise HTTPStatus::BadRequest, "extra data after chunk '#{line}'."
         end
 
         chunk_size, = read_chunk_size(socket)
diff --git a/lib/webrick/httpresponse.rb b/lib/webrick/httpresponse.rb
index dde0261d..4ad9cc2c 100644
--- a/lib/webrick/httpresponse.rb
+++ b/lib/webrick/httpresponse.rb
@@ -453,7 +453,7 @@ def error_body(backtrace, ex, host, port)
       _end_of_html_
 
       if backtrace && $DEBUG
-        @body << "backtrace of `#{HTMLUtils::escape(ex.class.to_s)}' "
+        @body << "backtrace of '#{HTMLUtils::escape(ex.class.to_s)}' "
         @body << "#{HTMLUtils::escape(ex.message)}"
         @body << "<PRE>"
         ex.backtrace.each{|line| @body << "\t#{line}\n"}
diff --git a/lib/webrick/httpserver.rb b/lib/webrick/httpserver.rb
index 0d261bf0..6d9dc26a 100644
--- a/lib/webrick/httpserver.rb
+++ b/lib/webrick/httpserver.rb
@@ -128,11 +128,11 @@ def service(req, res)
           do_OPTIONS(req, res)
           raise HTTPStatus::OK
         end
-        raise HTTPStatus::NotFound, "`#{req.unparsed_uri}' not found."
+        raise HTTPStatus::NotFound, "'#{req.unparsed_uri}' not found."
       end
 
       servlet, options, script_name, path_info = search_servlet(req.path)
-      raise HTTPStatus::NotFound, "`#{req.path}' not found." unless servlet
+      raise HTTPStatus::NotFound, "'#{req.path}' not found." unless servlet
       req.script_name = script_name
       req.path_info = path_info
       si = servlet.get_instance(self, *options)
diff --git a/lib/webrick/httpservlet/abstract.rb b/lib/webrick/httpservlet/abstract.rb
index 6fae4de9..280a4d3d 100644
--- a/lib/webrick/httpservlet/abstract.rb
+++ b/lib/webrick/httpservlet/abstract.rb
@@ -105,7 +105,7 @@ def service(req, res)
           __send__(method_name, req, res)
         else
           raise HTTPStatus::MethodNotAllowed,
-                "unsupported method `#{req.request_method}'."
+                "unsupported method '#{req.request_method}'."
         end
       end
 
diff --git a/lib/webrick/httpservlet/filehandler.rb b/lib/webrick/httpservlet/filehandler.rb
index 7ab88bca..4e759d8c 100644
--- a/lib/webrick/httpservlet/filehandler.rb
+++ b/lib/webrick/httpservlet/filehandler.rb
@@ -250,7 +250,7 @@ def do_GET(req, res)
 
       def do_POST(req, res)
         unless exec_handler(req, res)
-          raise HTTPStatus::NotFound, "`#{req.path}' not found."
+          raise HTTPStatus::NotFound, "'#{req.path}' not found."
         end
       end
 
@@ -307,7 +307,7 @@ def prevent_directory_traversal(req, res)
       end
 
       def exec_handler(req, res)
-        raise HTTPStatus::NotFound, "`#{req.path}' not found." unless @root
+        raise HTTPStatus::NotFound, "'#{req.path}' not found." unless @root
         if set_filename(req, res)
           handler = get_handler(req, res)
           call_callback(:HandlerCallback, req, res)
@@ -359,7 +359,7 @@ def set_filename(req, res)
             call_callback(:FileCallback, req, res)
             return true
           else
-            raise HTTPStatus::NotFound, "`#{req.path}' not found."
+            raise HTTPStatus::NotFound, "'#{req.path}' not found."
           end
         end
 
@@ -368,8 +368,8 @@ def set_filename(req, res)
 
       def check_filename(req, res, name)
         if nondisclosure_name?(name) || windows_ambiguous_name?(name)
-          @logger.warn("the request refers nondisclosure name `#{name}'.")
-          raise HTTPStatus::NotFound, "`#{req.path}' not found."
+          @logger.warn("the request refers nondisclosure name '#{name}'.")
+          raise HTTPStatus::NotFound, "'#{req.path}' not found."
         end
       end
 
@@ -437,7 +437,7 @@ def nondisclosure_name?(name)
       def set_dir_list(req, res)
         redirect_to_directory_uri(req, res)
         unless @options[:FancyIndexing]
-          raise HTTPStatus::Forbidden, "no access permission to `#{req.path}'"
+          raise HTTPStatus::Forbidden, "no access permission to '#{req.path}'"
         end
         local_path = res.filename
         list = Dir::entries(local_path).collect{|name|
diff --git a/lib/webrick/httputils.rb b/lib/webrick/httputils.rb
index 92f3044d..e2c2a407 100644
--- a/lib/webrick/httputils.rb
+++ b/lib/webrick/httputils.rb
@@ -29,14 +29,14 @@ module HTTPUtils
     # normalized.
 
     def normalize_path(path)
-      raise "abnormal path `#{path}'" if path[0] != ?/
+      raise "abnormal path '#{path}'" if path[0] != ?/
       ret = path.dup
 
       ret.gsub!(%r{/+}o, '/')                    # //      => /
       while ret.sub!(%r'/\.(?:/|\Z)', '/'); end  # /.      => /
       while ret.sub!(%r'/(?!\.\./)[^/]+/\.\.(?:/|\Z)', '/'); end # /foo/.. => /foo
 
-      raise "abnormal path `#{path}'" if %r{/\.\.(/|\Z)} =~ ret
+      raise "abnormal path '#{path}'" if %r{/\.\.(/|\Z)} =~ ret
       ret
     end
     module_function :normalize_path
diff --git a/lib/webrick/server.rb b/lib/webrick/server.rb
index f085d5d2..3fe268dc 100644
--- a/lib/webrick/server.rb
+++ b/lib/webrick/server.rb
@@ -365,7 +365,7 @@ def cleanup_listener
         begin
           s.shutdown
         rescue Errno::ENOTCONN
-          # when `Errno::ENOTCONN: Socket is not connected' on some platforms,
+          # when 'Errno::ENOTCONN: Socket is not connected' on some platforms,
           # call #close instead of #shutdown.
           # (ignore @config[:ShutdownSocketWithoutClose])
           s.close
diff --git a/test/webrick/test_filehandler.rb b/test/webrick/test_filehandler.rb
index 3b299d93..db7618d2 100644
--- a/test/webrick/test_filehandler.rb
+++ b/test/webrick/test_filehandler.rb
@@ -188,7 +188,7 @@ def test_filehandler
   def test_non_disclosure_name
     config = { :DocumentRoot => File.dirname(__FILE__), }
     log_tester = lambda {|log, access_log|
-      log = log.reject {|s| /ERROR `.*\' not found\./ =~ s }
+      log = log.reject {|s| /ERROR '.*' not found\./ =~ s }
       log = log.reject {|s| /WARN  the request refers nondisclosure name/ =~ s }
       assert_equal([], log)
     }
@@ -220,7 +220,7 @@ def test_directory_traversal
     config = { :DocumentRoot => File.dirname(__FILE__), }
     log_tester = lambda {|log, access_log|
       log = log.reject {|s| /ERROR bad URI/ =~ s }
-      log = log.reject {|s| /ERROR `.*\' not found\./ =~ s }
+      log = log.reject {|s| /ERROR '.*' not found\./ =~ s }
       assert_equal([], log)
     }
     TestWEBrick.start_httpserver(config, log_tester) do |server, addr, port, log|
@@ -249,7 +249,7 @@ def test_short_filename
     return if File.executable?(__FILE__) # skip on strange file system
 
     log_tester = lambda {|log, access_log|
-      log = log.reject {|s| /ERROR `.*\' not found\./ =~ s }
+      log = log.reject {|s| /ERROR '.*' not found\./ =~ s }
       log = log.reject {|s| /WARN  the request refers nondisclosure name/ =~ s }
       assert_equal([], log)
     }
@@ -346,7 +346,7 @@ def req.meta_vars
       },
     }
     log_tester = lambda {|log, access_log|
-      log = log.reject {|s| /ERROR `.*\' not found\./ =~ s }
+      log = log.reject {|s| /ERROR '.*' not found\./ =~ s }
       assert_equal([], log)
     }
     TestWEBrick.start_httpserver(config, log_tester) do |server, addr, port, log|
@@ -382,7 +382,7 @@ def req.meta_vars
   def test_erbhandler
     config = { :DocumentRoot => File.dirname(__FILE__) }
     log_tester = lambda {|log, access_log|
-      log = log.reject {|s| /ERROR `.*\' not found\./ =~ s }
+      log = log.reject {|s| /ERROR '.*' not found\./ =~ s }
       assert_equal([], log)
     }
     TestWEBrick.start_httpserver(config, log_tester) do |server, addr, port, log|
diff --git a/test/webrick/test_httpserver.rb b/test/webrick/test_httpserver.rb
index 0c5a6147..71c9f31b 100644
--- a/test/webrick/test_httpserver.rb
+++ b/test/webrick/test_httpserver.rb
@@ -237,8 +237,8 @@ def test_callbacks
       :RequestCallback => Proc.new{|req, res| requested0 += 1 },
     }
     log_tester = lambda {|log, access_log|
-      assert(log.find {|s| %r{ERROR `/' not found\.} =~ s })
-      assert_equal([], log.reject {|s| %r{ERROR `/' not found\.} =~ s })
+      assert(log.find {|s| %r{ERROR '/' not found\.} =~ s })
+      assert_equal([], log.reject {|s| %r{ERROR '/' not found\.} =~ s })
     }
     TestWEBrick.start_httpserver(config, log_tester){|server, addr, port, log|
       vhost_config = {
@@ -411,7 +411,7 @@ def test_request_handler_callback_is_deprecated
     log_tester = lambda {|log, access_log|
       assert_equal(2, log.length)
       assert_match(/WARN  :RequestHandler is deprecated, please use :RequestCallback/, log[0])
-      assert_match(%r{ERROR `/' not found\.}, log[1])
+      assert_match(%r{ERROR '/' not found\.}, log[1])
     }
     TestWEBrick.start_httpserver(config, log_tester){|server, addr, port, log|
       Thread.pass while server.status != :Running
@@ -465,7 +465,7 @@ def test_cntrl_in_path
     http = Net::HTTP.new(addr[3], addr[1])
     req = Net::HTTP::Get.new('/notexist%0a/foo')
     http.request(req) { |res| assert_equal('404', res.code) }
-    exp = %Q(ERROR `/notexist\\n/foo' not found.\n)
+    exp = %Q(ERROR '/notexist\\n/foo' not found.\n)
     assert_equal 1, log_ary.size
     assert_include log_ary[0], exp
   ensure