In order to provide an electric vehicle drive system capable of promoting improvement in stability of vehicle traveling when stopping a regeneration operation during operation of a regeneration cooperative brake, the electric vehicle drive system, a battery control unit 310, upon detecting that a battery state is an unchargeable state during control of the regeneration cooperative brake, diagnoses whether a battery 300 is chargeable, and upon deciding to be unchargeable from a result of diagnosis, outputs a Fail signal. Then, a rotating electrical machine control unit 210, upon receiving a Fail prediction signal while the regeneration cooperative brake is being controlled, executes loss increase control for increasing an internal loss of a rotating electrical machine 900 and reducing regenerative electric power by a regenerative brake while maintaining torque of the rotating electrical machine 900 at regenerative torque corresponding to regenerative brake force.