The present invention provides a driving force distributing apparatus which can instantaneously reduce clutch pressure to thereby carry out proper operation of an ABS even if the ABS is actuated in traveling in a 4WD mode. In order to reduce pressure in a piston chamber, a control circuit drives a motor for reverse rotation. As a result, a pressure difference between a piston chamber side pressure and a pump side pressure in a supply path becomes large, pressure oil on a piston chamber side in the supply path is instantaneously discharged to an outside from a releasing hole of a quick open valve, and the pressure in the piston chamber reduces instantaneously.