In a control drive circuit for an electric power tool, a bridge-structured motor, which has a bridge structure and includes switching elements and a motor body, is connected to a power supply unit without any mechanical contacts, and an electric power is supplied to a control circuit for controlling the switching elements by turning on a trigger switch. Further, a circuit switch is provided at power supply sides of drive circuits for driving the switching elements, the circuit switch being controlled by the control circuit to interrupt supply of the electric power to the drive circuits.