A lockup control device for a torque converter, which is provided with a lockup clutch engageable to connect a pump at the torque converter directly with a turbine thereat and disengageable to release the direct connection of the pump and turbine, and with an actuating device comprising a car speed detector which detects car speed to output a plurality of car speed signals, a negative pressure detector which detects a suction pipe negative pressure to output a plurality of negative pressure signals, and an actuator operable in response to the car speed and negative pressure signals, so that, on a basis of the car speed and negative pressure signals output from the respective detectors, the clutch is engaged when the car speed is greater than or equal to a predetermined speed and the suction pipe negative pressure is greater than or equal to a predetermined pressure, and is disengaged when the car speed is less than the predetermined speed and the negative pressure is less than the predetermined pressure.