The engine starter includes a pinion-mobile component which is linked to an output shaft by a helical spline and can be slid in a shaft direction, in a state where the pinion-mobile component includes; an overrunning clutch which is idled when the pinion gear, which is engaged to the ring gear, is driven by the engine via the ring gear so as to be rotated at a rotational speed which is higher than a rotational speed of the output shaft; and a breaking mechanism in which the overrunning clutch breaks a transmission of a torque, which is generated in accordance with a rotation of the motor and is transmitted to the ring gear, when a value of the torque is a predetermined condition value with respect to a direction where the torque is transmitted to the ring gear.