In an automatic transmission control system, an operating amount of a throttle due to a driver's depression of an accelerator pedal is detected, and the rotating number of an engine suitable for the detected throttle operating amount is detected. The automatic transmission control system includes a shift map defined by the throttle operating amount and the engine rotating number. The actuation of upshift or downshift of a transmission is automatically controlled based on the shift map. The driver can be informed of a point where a shift map is switched by a depression operation of the accelerator pedal so that generation of unnecessary downshift and delay of upshift are prevented to allow a vehicle to be efficiently driven.