An object of the invention is to increase the recovered kinetic energy as much as possible in a regeneration control system for a vehicle that converts the kinetic energy of a wheel into electrical energy while the vehicle is decelerating. To achieve the object, in the invention, the electric energy generated by a generator is decreased at the time when the wheel slips. In consequence, the recovered kinetic energy can be made larger as compared to the case where the electric energy generated by the generator is decreased based on an anticipation of slippage of the wheel made in advance.