A cooling fluid pump in which a cooling fluid is caused to flow to cool a heating element includes a casing brought into a direct contact or an indirect contact via a heat transfer member with the heating element, a pump chamber defined in the casing, an impeller rotatably mounted in the pump chamber and including a pump groove formed in either one of both axial end faces, the impeller having an axis of rotation located radially away from a center of the casing, an inlet formed in the casing so that the cooling fluid is supplied through the inlet into the pump chamber by an action of the pump groove with rotation of the impeller, and an outlet formed in the casing so that the cooling fluid is discharged through the outlet out of the pump chamber by an action of the pump groove with rotation of the impeller.