A control apparatus for controlling a transmission apparatus that includes: an input member that is drivably connected to a rotating electrical machine being capable of generating regenerative torque based on an engine and a deceleration request of a vehicle; an output member that is drivably connected to wheels; and a speed change mechanism that has a plurality of friction engagement elements that are controlled to be engaged and released so as to switch a plurality of shift speeds, and that shifts a rotation speed of the input member at one of gear ratios set for the shift speeds and outputs the shifted speed to the output member.