A vehicle having an electric generator control apparatus is provided for gradually reducing an engine load imposed due to electricity generation while a throttle valve is in the process of becoming fully open, thereby increasing a vehicle acceleration capability. The electric generator control apparatus is incorporated in a vehicle which has an ACG starter motor for generating electric power from power of an engine and supplying the generated electric power to a battery and other electric loads. When an engine throttle opening exceeds a preset value, the electric generator control apparatus continuously gradually reduces the amount of electric power generated by the ACG starter motor depending on the throttle opening in a fully opening direction which exceeds the preset value. The load imposed on the engine by electricity generation is gradually reduced, resulting in a corresponding increase in the acceleration capability of the vehicle.