An oil supply device for an engine is provided with an oil pump of a variable capacity type; a plurality of hydraulically operated devices connected to the pump via an oil path; a pump control unit which changes the capacity of the pump to control a discharge amount of oil; and a hydraulic pressure detecting unit which detects a hydraulic pressure of the oil path. The plurality of the hydraulically operated devices include a metal bearing, and the pump control unit sets a highest requested hydraulic pressure among requested hydraulic pressures of the hydraulically operated devices as a target hydraulic pressure for each of the operating conditions of the engine, and changes the capacity of the pump in such a manner that the hydraulic pressure detected by the hydraulic pressure detecting unit coincides with the target hydraulic pressure for controlling the discharge amount.