PURPOSE: To cheaply control learning concerning the working pressure of a frictional element for selecting a high speed step for keeping a torque phase time at a set value when speed is changed to up-shift by changeover of the frictional element.

CONSTITUTION: At speed change of 2→3 up-shift performed by changeover from a second brake S/B to a band brake B/B, a controller 60 measures a torque phase time from a speed change beginning moment in which high speed step selecting pressure PB/B reaches the setting value and a pressure switch 63 is ON, to an inertia phase beginning moment by means of a self-contained timer, controls learning concerning the pressure PB/B to the chamber 3A of the band brake B/B in the torque phase so that the torque phase time becomes the setting value, and contributes to a solenoid valve 50.