An electrode surface of a horizontal semiconductor chip and a substrate are joined together through a plurality of first joint portions including a plurality of joint portions at which a plurality of electrodes formed on the electrode surface are joined to the substrate. A no-electrode surface of the horizontal semiconductor chip and a heatsink are joined together through a second joint portion at which the no-electrode surface and the heatsink are joined together. In a plan view from a direction normal to a principal surface of the substrate, when a region inside the outline of the rough shape of an aggregate of the first joint portions is a first joint region and a region inside the outline of the second joint portion is a second joint region, the first joint region and the second joint region are the same in position, shape, and size.