A rear electric brake electronic control unit (ECU) includes a delay circuit between a microcomputer of the rear electric brake ECU and a switch for driving a solenoid of a parking mechanism. The delay circuit is configured to delay a signal for driving the switch. The rear electric brake ECU further includes a diagnosis circuit for diagnosing an actuation state of the microcomputer. The diagnosis circuit is able to shut off a power supply to the solenoid regardless of a state of a signal of the solenoid if the actuation state of the microcomputer is abnormal.