ENGINE STARTING DEVICE AND VEHICLE MOUNTED WITH SAME

A device for starting an engine (100) includes a starter (200) for starting the engine (100) and an ECU (300). The starter (200) includes a pinion gear (260) for engagement with a ring gear (110) for cranking the engine (100), an actuator (232) structured to engage the pinion gear (260) with a ring gear (110), and a motor (220) for rotating the pinion gear (260). The actuator (232) and the motor (220) can individually be controlled. The ECU (300) has a rotation mode for driving the motor (220) prior to drive of the actuator (232) and an engagement mode for causing the actuator (232) to engage the pinion gear (260) and the ring gear (110) with each other prior to drive of the motor (220). When a request to start the engine (100) is made, the ECU (300) switches selection between the rotation mode and the engagement mode based on a rotation speed of the engine (100) and a reduction rate in rotation speed of the engine (100).