diff --git a/onlinejudge_verify/languages/cplusplus.py b/onlinejudge_verify/languages/cplusplus.py
index ecbafc6c..1aebf80f 100644
--- a/onlinejudge_verify/languages/cplusplus.py
+++ b/onlinejudge_verify/languages/cplusplus.py
@@ -27,7 +27,7 @@ def __init__(self, *, CXX: pathlib.Path, CXXFLAGS: List[str]):
         self.CXXFLAGS = CXXFLAGS
 
     def compile(self, path: pathlib.Path, *, basedir: pathlib.Path, tempdir: pathlib.Path) -> None:
-        command = [str(self.CXX), *self.CXXFLAGS, '-I', str(basedir), '-o', str(tempdir / 'a.out'), str(path)]
+        command = [str(self.CXX), *self.CXXFLAGS, '-liconv', '-I', str(basedir), '-o', str(tempdir / 'a.out'), str(path)]
         logger.info('$ %s', ' '.join(command))
         subprocess.check_call(command)