A cooling device has a closed circulating channel for circulating coolant, and in the channel, a radiator and a contact-heat-exchanger type centrifugal pump are provided. A heat-producing electronic component contacts with the centrifugal pump, and the coolant in the pump collects the heat off the component due to the heat exchanging function. Then the heat is dissipated from the radiator. The pump includes a pump-casing made of highly heat conductive material and an impeller. The pump casing has a base wall and a cover wall opposite the base wall. The base wall has an outer wall face constituting a heat-receiving face, and an inner wall face facing the impeller. The impeller is disposed in a pump room defined between the base wall and cover wall of the casing. A sucking channel is provided between the heat-receiving face and an inner wall face of the pump room. This inner wall has a recess where protrusions extending toward the impeller or dimples are provided.