diff --git a/main.cpp b/main.cpp
index dd1c9c8d2..a83db0e81 100644
--- a/main.cpp
+++ b/main.cpp
@@ -11,11 +11,6 @@
 #include <string>
 #include <vector>
 #include <sentencepiece_processor.h>
-#include <stdexcept>
-#include <iostream>
-#include <bitset>
-#include <sstream>
-#include <regex>
 
 #if defined (__unix__) || (defined (__APPLE__) && defined (__MACH__))
 #include <signal.h>
diff --git a/utils.cpp b/utils.cpp
index bd449bdce..4c2823d92 100644
--- a/utils.cpp
+++ b/utils.cpp
@@ -5,11 +5,6 @@
 #include <fstream>
 #include <regex>
 #include <sentencepiece_processor.h>
-#include <sstream>
-#include <iostream>
-#include <iterator>
-#include <string>
-#include <math.h>
 
  #if defined(_MSC_VER) || defined(__MINGW32__)
  #include <malloc.h> // using malloc.h with MSC/MINGW
diff --git a/utils.h b/utils.h
index 0c8ba8c21..2511c2941 100644
--- a/utils.h
+++ b/utils.h
@@ -8,7 +8,6 @@
 #include <random>
 #include <thread>
 #include <sentencepiece_processor.h>
-#include <sstream>
 
 //
 // CLI argument parsing