To provide a battery power tool improving use convenience, by providing a discharge stop voltage control circuit to forcedly stop a discharge when battery voltage is lowered down, also providing a brake control circuit to supply kinetic energy at braking time to a battery as electric energy.

A switching element 13 is connected in series to a motor 2, and a discharge stop voltage control circuit 15 is connected in parallel to a potential pack 9. The switching element 13 is turned on when voltage of the potential pack 9 is a specified value or more and turned off when it is the specified value or less by an output of the discharge stop voltage control circuit 15, also a brake control circuit 16 is provided in parallel to the potential pack 9, and kinetic energy of the motor 2 is supplied to the potential pack 9 as electric energy when a common terminal 4c and a brake terminal 4b are connected in a switch 4.