To provide a transmission control device of an automatic transmission which considerably reduces transmission shock by optimizing the timing for reducing engine torque upon changing gears.

In the transmission control device of the automatic transmission according to the present invention that reduces the engine torque Te by controlling an engine 10 by means of a controller 100 while changing input from the engine 10 by tightening or releasing a plurality of friction elements arranged in the automatic transmission 20, a motor 1 controlled by the controller 100 is provided in a three-speed/five-speed/rear band brake 35R/B, so that the tightening and releasing the brake 35R/B is controlled by the number of steps S of the motor 1. When the number of steps S of the motor 1 becomes greater than a predetermined value S1, the reduction of the engine torque Te is started by reducing the opening TVO of a throttle valve 12 by the controller 100.