diff --git a/dynamixel_manager/include/modules/motion_pages.h b/dynamixel_manager/include/modules/motion_pages.h
index 56f8febe2818fe91a67ca43c686cd058da8567ca..9edefcb230b1028f4364ae76de7ac0f4a534b177 100755
--- a/dynamixel_manager/include/modules/motion_pages.h
+++ b/dynamixel_manager/include/modules/motion_pages.h
@@ -35,7 +35,7 @@ typedef struct // Header Structure (total 64unsigned char)
 
 typedef struct // Step Structure (total 64unsigned char)
 {
-  short int position[PAGE_MAX_NUM_SERVOS];    // Joint position   0~61
+  unsigned short int position[PAGE_MAX_NUM_SERVOS];    // Joint position   0~61
   unsigned char pause;            // Pause time       62
   unsigned char time;             // Time             63
 }TStep;