Shift control system for automatic transmission

1. Field of the Invention A shift control system for an automatic transmission which has a gear ratio control means for controlling gear ratio of the automatic transmission comprises a lower limit setting device provided in said gear ratio control means and setting a lower limit for inhibiting a gear ratio from changing to a gear ratio of an upshift side; and a lower limit variable control means in which a lower limit of said gear ratio can be changed to a downshift side or to an upshift side by an operation of a driver.