Disclosed herein is a method of calibrating a robot. The robot has a robot arm with a mechanically restricted moving displacement. In the robot calibration method of the present invention, a first moving displacement between a normal position of the robot arm and a contact position, where the robot arm comes into contact with the body of the robot, is obtained. A second moving displacement between a current position of the robot arm and the contact position is obtained by moving the robot arm to the contact position. The current position of the robot arm is corrected to the normal position on the basis of a difference between the first and second moving displacements.