To increase cooling performance of an oil cooler by reducing the temperature of cooling water for cooling the oil cooler while simplifying the layout of piping.

In a cooling device for the vehicular oil cooler for supplying the cooling water from a cooling water outlet formed in a vehicle-width-direction end of the engine to the oil cooler via oil cooler inlet piping, by horizontally loading the engine behind a radiator disposed on an engine room front surface part, and attaching an exhaust manifold and the oil cooler to a vehicle-front-side side surface of the engine, radiator outlet piping for returning the cooling water cooled by the radiator to the engine is disposed in the vicinity of the cooling water outlet in a state of extending in a lengthwise direction of the vehicle, the oil cooler inlet piping is disposed in the lengthwise direction of the vehicle along an outer peripheral surface of the radiator outlet piping, and the oil cooler inlet piping is disposed on the opposite side of the exhaust manifold relative to the radiator outlet piping.