To restrict the lowering of fuel economy of an engine, and to restrict the lowering of durability of a torque capacity control device in a case that the torque capacity control device is provided on an output side of the engine, of which total displacement can be changed.

This controller for a power train for vehicle having the engine, of which total displacement can be changed, and the torque capacity control device which changes a torque capacity, is provided with a total displacement control means (step S7) for determining whether the total displacement of the engine is changed, and a first propriety determining means (step S8) for determining whether control for changing the torque capacity of the torque capacity control means on the basis of a change of the torque transmitted to the torque capacity control device is done on the basis of a result of the determination of the total displacement control means.