To provide a cooling device of a vehicle engine, in which air mixed in cooling water piping of a cooling device is easily removed and an air vent hose is protected when external force is exerted on a vehicle.

The cooling device of a vehicle engine includes: a radiator arranged in the front of an engine compartment of the vehicle; a turbocharger attached to the front side of the engine mounted behind the radiator; an air cleaner connected to the side face of the turbocharger in the width direction of the vehicle; a gas-liquid separation tank arranged on the side of the air cleaner; the cooling water piping for connecting the engine to the radiator; and the air vent hose for connecting the radiator to the gas-liquid separation tank. An air intake hose is bent into an S shape or crank-like shape in a vehicle front view, a radiator-side connection part to which the air vent hose is connected, is disposed to face the space surrounded by the air intake hose and the air cleaner, and the air vent hose is put through the surrounded space and connected to the radiator-side connection part.