A reverse-engaging condition is prevented by a reverse inhibit valve operated by the solenoid valve even if a shift lever is operated to a reverse range at forward running. A solenoid valve controlling a 1-2 shift valve is "OFF" when controlling a manual valve to a reverse range under 7 km/h of a vehical speed. The reverse inhibit valve is at a right-half position. Therefore, the hydraulic pressure from the reverse range port of the manual valve runs through oil passages and supplied to the hydraulic servos. At forward running over 7 km/h the solenoid valve is switched "ON", the reverse inhibit valve is switched to a left-half position and oil passages are isolated. When the solenoid valve is switched at forward running, a hydraulic pressure from a R range port of the manual valve does not operate on a difference of cross sectional areas of lands of the reverse inhibit valve, so that the reverse inhibit valve is kept at the right-half position together with a pressing force of a spring therein.