diff --git a/CHANGELOG.md b/CHANGELOG.md
index 334eb1fb93..4acba9fc89 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -47,6 +47,9 @@
 * Improve performance of `FunctionParameterCountRule`.  
   [Norio Nomura](https://github.com/norio-nomura)
 
+* Improve performance of `ColonRule`.  
+  [Norio Nomura](https://github.com/norio-nomura)
+
 ##### Bug Fixes
 
 * Fix case sensitivity of keywords for `valid_docs`.  
diff --git a/Source/SwiftLintFramework/Extensions/File+SwiftLint.swift b/Source/SwiftLintFramework/Extensions/File+SwiftLint.swift
index 47a04e85fe..e543d32f59 100644
--- a/Source/SwiftLintFramework/Extensions/File+SwiftLint.swift
+++ b/Source/SwiftLintFramework/Extensions/File+SwiftLint.swift
@@ -73,23 +73,33 @@ extension File {
         }.map { $0.0 }
     }
 
-    public func matchPattern(pattern: String) -> [(NSRange, [SyntaxKind])] {
-        return matchPattern(regex(pattern))
+    internal func rangesAndTokensMatching(pattern: String) -> [(NSRange, [SyntaxToken])] {
+        return rangesAndTokensMatching(regex(pattern))
     }
 
-    public func matchPattern(regex: NSRegularExpression) -> [(NSRange, [SyntaxKind])] {
+    internal func rangesAndTokensMatching(regex: NSRegularExpression) ->
+        [(NSRange, [SyntaxToken])] {
         let contents = self.contents as NSString
         let range = NSRange(location: 0, length: contents.length)
         let syntax = syntaxMap
-        let matches = regex.matchesInString(self.contents, options: [], range: range)
-        return matches.map { match in
+        return regex.matchesInString(self.contents, options: [], range: range).map { match in
             let matchByteRange = contents.NSRangeToByteRange(start: match.range.location,
                 length: match.range.length) ?? match.range
-            let kindsInRange = syntax.tokens.filter { token in
+            let tokensInRange = syntax.tokens.filter { token in
                 let tokenByteRange = NSRange(location: token.offset, length: token.length)
                 return NSIntersectionRange(matchByteRange, tokenByteRange).length > 0
-            }.map({ $0.type }).flatMap(SyntaxKind.init)
-            return (match.range, kindsInRange)
+            }.map({ $0 })
+            return (match.range, tokensInRange)
+        }
+    }
+
+    public func matchPattern(pattern: String) -> [(NSRange, [SyntaxKind])] {
+        return matchPattern(regex(pattern))
+    }
+
+    public func matchPattern(regex: NSRegularExpression) -> [(NSRange, [SyntaxKind])] {
+        return rangesAndTokensMatching(regex).map { range, tokens in
+            (range, tokens.map({ $0.type }).flatMap(SyntaxKind.init))
         }
     }
 
diff --git a/Source/SwiftLintFramework/Rules/ColonRule.swift b/Source/SwiftLintFramework/Rules/ColonRule.swift
index 1357f93bc6..3a8092fc4f 100644
--- a/Source/SwiftLintFramework/Rules/ColonRule.swift
+++ b/Source/SwiftLintFramework/Rules/ColonRule.swift
@@ -111,25 +111,32 @@ public struct ColonRule: CorrectableRule, ConfigProviderRule {
     // MARK: - Private
 
     private let pattern =
-        "(\\w+)" + // Capture an identifier
-        "(?:" +    // start group
-        "\\s+" +   // followed by whitespace
-        ":" +      // to the left of a colon
-        "\\s*" +   // followed by any amount of whitespace.
-        "|" +      // or
-        ":" +      // immediately followed by a colon
+        "(\\w)" +              // Capture an identifier
+        "(?:" +                // start group
+        "\\s+" +               // followed by whitespace
+        ":" +                  // to the left of a colon
+        "\\s*" +               // followed by any amount of whitespace.
+        "|" +                  // or
+        ":" +                  // immediately followed by a colon
         "(?:\\s{0}|\\s{2,})" + // followed by 0 or 2+ whitespace characters.
-        ")" +      // end group
-        "(" +      // Capture a type identifier
-        "(?:\\[|\\()*" + // which may begin with a series of nested parenthesis or brackets
-        "\\S+?)"   // lazily to the first non-whitespace character.
+        ")" +                  // end group
+        "(" +                  // Capture a type identifier
+        "[\\[|\\(]*" +         // which may begin with a series of nested parenthesis or brackets
+        "\\S)"                 // lazily to the first non-whitespace character.
 
     private func violationRangesInFile(file: File, withPattern pattern: String) -> [NSRange] {
-        return file.matchPattern(pattern).filter { range, syntaxKinds in
+        let nsstring = file.contents as NSString
+        let commentAndStringKindsSet = Set(SyntaxKind.commentAndStringKinds())
+        return file.rangesAndTokensMatching(pattern).filter { range, syntaxTokens in
+            let syntaxKinds = syntaxTokens.map({ $0.type }).flatMap(SyntaxKind.init)
             if !syntaxKinds.startsWith([.Identifier, .Typeidentifier]) {
                 return false
             }
-            return Set(syntaxKinds).intersect(Set(SyntaxKind.commentAndStringKinds())).isEmpty
-        }.flatMap { $0.0 }
+            return Set(syntaxKinds).intersect(commentAndStringKindsSet).isEmpty
+        }.flatMap { range, syntaxTokens in
+            let identifierRange = nsstring // swiftlint:disable:next force_unwrapping
+                .byteRangeToNSRange(start: syntaxTokens.first!.offset, length: 0)
+            return identifierRange.map { NSUnionRange($0, range) }
+        }
     }
 }