Provided is a motor generator, which is always connected to an engine via a belt, and is configured to carry out start control of the engine and power generation control, the motor generator having a two-output power transmission mechanism including: a belt driving mechanism, which is configured to drive the engine through the belt; and a gear driving mechanism, which includes a pinion gear to be coupled to a ring gear on the engine side in accordance with an external instruction, and is configured to drive the engine by the pinion gear being coupled to the ring gear, in which an output of the belt driving mechanism and an output of the gear driving mechanism are arranged at positions opposing each other in an axial direction of a rotor of the motor generator.