The invention provides a method and device for controlling automatic transmission, which aims at reducing the impact of the engagement, shortening the engagement control time, simplifying the control and reducing and miniaturization of the manufacturing cost. In the engagement action of the second brake, the oil pressure control department responds to the change of speed when the change of speed command is issued at time t0, and sends the oil pressure command ( first process ) of oil pressure level L4 to the linear solenoid valve within the first period of time t0 to time t5.In the second period from the time T5 to the time T6, a hydraulic pressure command is issued to the linear solenoid valve from the hydraulic pressure level L4 to the hydraulic pressure level L6 with time (from the hydraulic pressure level L4 to the hydraulic pressure level L6) (second step). On the other hand, the engagement operation of the first brake is the control including the pre-pressurization process. The length of the first period during the engagement operation of the second brake is shorter than the period during which the pressure increasing step is started after the speed change command is received during the engagement operation of the first brake.