In an engine-starting and stopping system in a vehicle, a crank pulley for driving auxiliary parts by an endless belt is mounted at an end of a crankshaft protruding from a cylinder block of an engine, and a starter motor for cranking the crankshaft is accommodated in an internal space in the crank pulley. The starter motor includes a rotor having a permanent magnet fixed to an inner peripheral surface of a peripheral wall of the crank pulley, and a stator having a coil fixed to an outer surface of a chain cover. Thus, the starter motor for automatically carrying out the restarting of the engine after stopping of the engine can be laid out compactly.