A vehicle transmission device includes an input member coupled to a combustion engine and a rotary electric machine; an output member coupled to wheels; a speed change mechanism with a plurality of friction engagement elements and that provides a plurality of shift speeds; and a control device that controls the speed change mechanism. When a during-regeneration downshift is performed while the rotary electric machine is outputting regenerative torque, the control device sets a target increase capacity, which is a target value of a transfer torque capacity of an engagement-side element to be engaged after an increase, increases the transfer torque capacity of the engagement-side element to the target increase capacity over a predetermined torque capacity increase period, and decreases a transfer torque capacity of a disengagement-side element, which is to be disengaged, over a predetermined torque capacity decrease period that at least partially overlaps the torque capacity increase period.