diff --git a/ginza/command_line.py b/ginza/command_line.py
index 856b574..8db72e6 100644
--- a/ginza/command_line.py
+++ b/ginza/command_line.py
@@ -62,6 +62,11 @@ def run(
     files: List[str] = None,
 ):
     assert model_path is None or ensure_model is None
+    if output_format in ["3", "json"] and hash_comment != "analyze":
+        print(
+            f'hash_comment="{hash_comment}" not permitted for JSON output. Forced to use hash_comment="analyze".',
+            file=sys.stderr
+        )
 
     if parallel_level <= 0:
         level = max(1, cpu_count() + parallel_level)
diff --git a/ginza/tests/test_command_line.py b/ginza/tests/test_command_line.py
index 2bd5484..b9ea14e 100644
--- a/ginza/tests/test_command_line.py
+++ b/ginza/tests/test_command_line.py
@@ -56,7 +56,7 @@ def output_file(tmpdir: Path) -> Path:
 
 def _conllu_parsable(result: str):
     for line in result.split("\n"):
-        if line.startswith("# text = ") or line.strip() == "":
+        if line.startswith("#") or line.strip() == "":
             continue
         if not len(line.strip().split("\t")) == 10:
             raise Exception
@@ -64,7 +64,7 @@ def _conllu_parsable(result: str):
 
 def _cabocha_parsable(result: str):
     for line in result.split("\n"):
-        if line.strip() in ("", "EOS") or line.startswith("*"):
+        if line.strip() in ("", "EOS") or line.startswith("*") or line.startswith("#"):
             continue
         if not len(line.split("\t")) == 3:
             raise Exception
@@ -74,7 +74,7 @@ def _cabocha_parsable(result: str):
 
 def _mecab_parsable(result: str):
     for line in result.split("\n"):
-        if line.strip() in ("", "EOS"):
+        if line.strip() in ("", "EOS") or line.startswith("#"):
             continue
         if not len(line.split("\t")) == 2:
             raise Exception
@@ -210,6 +210,18 @@ def test_output_format(self, output_format, result_parsable, input_file):
         assert p.returncode == 0
         result_parsable(p.stdout.strip())
 
+    @pytest.mark.parametrize(
+        "hash_comment", ["print", "skip"]
+    )
+    def test_warn_if_json_hash_comment_not_analyze(self, hash_comment, input_file):
+        p = run_cmd(["ginza", "-c", hash_comment, "-f", "json", input_file], stderr=sp.PIPE)
+        assert p.returncode == 0
+        msg = (
+            f'hash_comment={hash_comment} may break output json if input contains a line starts with "#".\n'
+            'In order to keep the json in proper format, please use hash_comment=analyze or remove the lines start with "#" from input.'
+        )
+        assert msg in p.stderr
+
     def test_require_gpu(self, input_file):
         p = run_cmd(["ginza", "-g", input_file])
         gpu_available = int(os.environ.get("CUDA_VISIBLE_DEVICES", -1)) > 0