diff --git a/requirements.txt b/requirements.txt
index 11abf2f..941ab36 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -18,7 +18,7 @@ kiwisolver>=1.3.2
 korean-lunar-calendar>=0.2.1
 matplotlib>=3.5.1
 munch>=2.5.0
-numpy>=1.21.5
+numpy>=1.21.5,<2
 openpyxl>=3.0.9
 packaging>=21.3
 pandas>=1.3.5
diff --git a/setup.py b/setup.py
index ebc4428..66d5420 100644
--- a/setup.py
+++ b/setup.py
@@ -45,7 +45,7 @@ def readme():
         'korean-lunar-calendar>=0.2.1',
         'matplotlib>=3.5.1',
         'munch>=2.5.0',
-        'numpy>=1.21.5',
+        'numpy>=1.21.5,<2',
         'openpyxl>=3.0.9',
         'packaging>=21.3',
         'pandas>=1.3.5',