To set an optimal shift characteristic, even when motor output is limited, while simplifying control algorithm.

Among a torque limiting value calculated with every parameter of a factor of limiting the motor output, a minimum value is calculated as motor assist possible torque TMLMT (S3), and the request torque ratio RTDMND is calculated on the basis of power unit maximum torque TPUMAX of adding the motor assist possible torque TMLMT to engine maximum torque TEGMAX (S4 to S9). A shift stage of an automatic transmission is determined by reading a shift chart with the request torque ratio RTDMND and a vehicle speed as a parameter (S10). Thus, the optimal gear ratio can be set by simple control algorithm even when an assist quantity of a motor is changed by various factors of limiting the motor output, and cost can be reduced, and controllability can be improved.