It is provided a control device for a power transmission device including a regenerative electric motor via a stepped shifting mechanism, wherein when a shift of the stepped shifting mechanism is performed in a regenerative state of the electric motor, the control device for a power transmission device increases an input shaft rotation speed of the stepped shifting mechanism through hydraulic control before a shift ending period, and, in the shift ending period, restrains an increase of the input shaft rotation speed through the hydraulic control and controls an input shaft rotation speed of the stepped shifting mechanism with the electric motor to be a target rotation speed after the shift.