A heat release device is for use with a multilayer board that has an inner layer serving as a power layer. The heat release device includes a heat release member thermally and electrically connected to the power layer, and a heat release board having a heat release layer and a shield layer electrically insulated from each other. The heat release layer is thermally and electrically connected to the heat release member. The shield layer serves to shield against electromagnetic noise radiated from the heat release layer. The shield layer is electrically insulated from the heat release member connected to the heat release layer. The heat release device also includes an electrically conductive member electrically connected to the shield layer and grounded, and an insulator through which the heat release layer is thermally connected to the electrically conductive member.