A control device of a vehicle drive device comprises a hydraulic power transmission device having an input-side rotating element to which power from an engine is input and an output-side rotating element outputting power to drive wheels, a first electric motor directly or indirectly coupled to the input-side rotating element, and a second electric motor directly or indirectly coupled to the drive wheels, the vehicle drive device further comprising an electric path through which power is electrically transmitted by giving/receiving electric power between the first electric motor and the second electric motor and a mechanical path through which power is mechanically transmitted via the hydraulic power transmission device, the control device of the vehicle drive device being configured to control an operating point of the engine by adjusting a torque of the first electric motor, the control device being configured to adjust the torque of the first electric motor such that a sum of an engine torque and the torque of the first electric motor is balanced with an input-side load torque generated in the input-side rotating element depending on a speed ratio of the hydraulic power transmission device when the operating point of the engine is controlled, the control device being configured to calculate the input-side load torque based on engine rotation speed indicated by the target engine operating point and determine the torque of the first electric motor based on the engine torque indicated by the target engine operating point and the input-side load torque, the vehicle drive device further comprising a capacity variable device varying a characteristic of a capacity coefficient of the hydraulic power transmission device relative to a speed ratio of the hydraulic power transmission device that is a hydraulic characteristic of the hydraulic power transmission device for determining the input-side load torque.