Abstract: A power take off device for an automatic transmission for taking off auxiliary power has a power take off switch which turns on the power take off device. The automatic transmission includes a torque converter and a lock-up clutch. The torque converter is connected to the power take off device when the power take off switch is turned on. The automatic transmission includes a lock-up control valve operating the lock-up clutch and a 1-2 shift valve for changing gear speed from a first stage to a second stage. The 1-2 shift valve supplies line pressure to the lock-up control valve when the shift lever is in the neutral position or the parking position and cuts off line pressure supplied to the lock-up control valve when the 1-2 shift valve is in the first stage.