An electric power generation control apparatus for a vehicle alternator mounted on a motor vehicle performs one of a constant output voltage control a constant torque control and a constant exciting current control in order to suppress a hunting phenomenon of the vehicle alternator. First of all, the electric power generation control apparatus performs the constant output voltage control when a rotation speed is within an idling rotation speed range or a periodic change of the rotation speed is not less than a predetermined value. After completion of the constant output voltage control, when judging that the idle hunting phenomenon is not adequately suppressed, the electric power generation control apparatus performs one of the constant torque control and the constant exciting current control.