diff --git a/soynlp/vectorizer/_word_context.py b/soynlp/vectorizer/_word_context.py
index f959516..99a2362 100644
--- a/soynlp/vectorizer/_word_context.py
+++ b/soynlp/vectorizer/_word_context.py
@@ -119,4 +119,4 @@ def _encode_as_matrix(word2contexts, vocab2idx, verbose):
         print('  - (word, context) matrix was constructed. shape = {}{}'.format(
             x.shape, ' '*20))
 
-    return x
\ No newline at end of file
+    return x.astype(float)