An engine stopping section first selects, when an engine stop condition is satisfied, a power-generation braking mode in which a power-generation braking torque is applied to the engine by a power generation operation of the generator, to thereby apply the power-generation braking torque to the engine, and then selects a short-circuit braking mode in which a short-circuit braking torque is applied to the engine by short-circuiting each energization phase of an armature coil with a semiconductor switch and by causing a field current to flow through a field coil, to thereby apply the short-circuit braking torque to the engine.