diff --git a/cocas/assembler/ast_builder.py b/cocas/assembler/ast_builder.py
index 7f37c401..4dc4a310 100644
--- a/cocas/assembler/ast_builder.py
+++ b/cocas/assembler/ast_builder.py
@@ -308,6 +308,8 @@ def encode_string(s: str, loc: CodeLocation) -> bytes:
                 result = result_
             else:
                 result = codecs.encode(result_, "utf-8")
+        except ValueError as e:
+            raise AssemblerException(AssemblerExceptionTag.ASM, loc.file, loc.line, str(e))
         except DeprecationWarning as e:
             raise AssemblerException(AssemblerExceptionTag.ASM, loc.file, loc.line, str(e))
         except UnicodeDecodeError as e: