An electronic device capable of efficiently cooling an integrated circuit element provided in such a way as to enable a heat exchange on a cold plate. The electronic device contains a circuit board mounted with an integrated circuit element requiring measures against heat generation in a single case, comprising: a cold plate mounted on the integrated circuit element in such a way as to enable a heat transfer from the integrated circuit element; a heat exchanger for cooling brine heated by the cold plate by circulating the brine; a fan casing forming an air way from a blower fan at an opening on a surface of the case to the heat exchanger; a reserve tank and a pump provided in order in a brine flow from the heat exchanger to the cold plate; and a linear brine passage formed in the cold plate and having at least one pair of back and forth channels.