An automatic stop/start controller having an engine, a motor generator to drive the engine, and an automatic transmission. The automatic stop/start controller permits the engine to stop and start without operation of an ignition key. At start of the engine by not operation of the ignition key and after the engine is started to drive by the motor generator, a control means corrects to increase the torque generated by the motor generator according to the degree of the engagement of frictional engaging elements of the automatic transmission.