Workpiece replacement device and workpiece replacement method

The invention relates to a workpiece replacement device and a workpiece replacement method for replacing a workpiece when a mechanical arm is utilized to wrap the inner side and the outer side of a wall of a machine tool. In the workpiece replacement device, a speed setting part sets the motion speed of the replacement mechanism to be a first speed when a position determination part determines that a replacement mechanism is positioned outside a cap, the speed setting part sets the motion speed of the replacement mechanism to be a second speed higher than the first speed when the position determination part determines that the replacement mechanism is not positioned outside the cap, and a control part controls the replacement mechanism to enable the replacement mechanism to be driven at the set speed. Therefore, the motion speed is low even if the replacement mechanism moves outside the cap. Therefore, the configuration position of the cap can be set within a motion region of the replacement mechanism, a guar