A control device for performing start assist control for an internal combustion engine includes: a first start assist processing unit that executes a first start assist process that brings a first engagement device into slip engagement at a first engagement pressure while increasing a torque generated by a rotating electrical machine; and a second start assist processing unit that increases, when the first start assist process fails to start the internal combustion engine, an engagement pressure of the first engagement device to a second engagement pressure higher than the first engagement pressure while increasing the torque generated by the rotating electrical machine. The second start assist processing unit determines the second engagement pressure on the basis of a rotational speed of the internal combustion engine in the first start assist process.