To provide a power tool setting or changing the rotational speed of a motor and the number of hitting only through an external device detachable from the power tool, storing the information on the rotational speed and the number of hitting during the actual operation in the storage means of the power tool, and reading and storing the information by the external device detachable from the power tool.

This power tool has a connector 9 for connecting, thereto, the external device 13 detachable therefrom. The storage means 8 stores the information on the rotational speed and the number of hitting to be set through the external device 13. A control signal output part outputs a control signal according to the rotational speed and the number of hitting stored by the storage means to output the rotational speed of the motor. Also, the storage means 8 stores the rotational speed and the number of hitting during the operation, and the external device 13 detachable from the power tool reads and stores the information.