diff --git a/Canon.Core/LexicalParser/SemanticToken.cs b/Canon.Core/LexicalParser/SemanticToken.cs
index 358c291..72d8cf3 100644
--- a/Canon.Core/LexicalParser/SemanticToken.cs
+++ b/Canon.Core/LexicalParser/SemanticToken.cs
@@ -215,8 +215,9 @@ public class NumberSemanticToken : SemanticToken
 
         bool hasDecimalPoint = false;
         bool hasExponent = false;
+        bool hasMinusSign = false;
 
-        while (now != null && (char.IsDigit(now.Value) || now.Value == '.' || now.Value == 'e' || now.Value == 'E'))
+        while (now != null && (char.IsDigit(now.Value) || now.Value == '.' || now.Value == 'e' || now.Value == 'E' || now.Value == '-' || now.Value == '+'))
         {
             if (now.Value == '.')
             {
@@ -236,6 +237,15 @@ public class NumberSemanticToken : SemanticToken
                 hasExponent = true;
             }
 
+            if (now.Value == '-' || now.Value == '+')
+            {
+                if (hasMinusSign)
+                {
+                    break;
+                }
+                hasMinusSign = true;
+            }
+
             buffer.Append(now.Value);
             now = now.Next;
         }
diff --git a/Canon.Tests/LexicalParserTests/NumberTests.cs b/Canon.Tests/LexicalParserTests/NumberTests.cs
index 9e8ab0f..eb2bd94 100644
--- a/Canon.Tests/LexicalParserTests/NumberTests.cs
+++ b/Canon.Tests/LexicalParserTests/NumberTests.cs
@@ -24,7 +24,7 @@ namespace Canon.Tests.LexicalParserTests
         [InlineData("1E-7", 1E-7, NumberType.Real)]
         [InlineData("1E", 0, NumberType.Real, false)]
         [InlineData("abc", 0, NumberType.Integer, false)]
-        [InlineData("123abc", 0, NumberType.Integer, false)]
+        [InlineData("123abc", 123, NumberType.Integer, true)]
         public void TestParseNumber(string input, double expected, NumberType expectedNumberType, bool expectedResult = true)
         {
             LinkedList<char> content = Utils.GetLinkedList(input);