The invention has an engine maximum torque calculating processor for calculating plural engine maximum torques showing a maximum value of engine torque, and an engine limit torque calculating processor for calculating a minimum value of the respective engine maximum torques as engine limit torque. Because the minimum value of the engine maximum torques is calculated as the engine limit torque, it is possible to reliably prevent the engine from entering an excessive rotating state. Further, because the engine limit torque is calculated on the basis of the minimum value of the engine maximum torques, the engine limit torque can be reliably calculated even when there is an individual difference in the engine, an electric generator, etc. and there are calculation errors further, for example, electric generator target torque and the electric generator maximum torque.