A semiconductor unit includes a cooler having a fluid flow space, an insulating substrate bonded to the cooler through a metal, a semiconductor device soldered to the insulating substrate, an intermediate member interposed between the insulating substrate and the fluid flow space and having a first surface where the insulating substrate is mounted, and a mold resin having a lower coefficient of liner expansion than the intermediate member. The insulating substrate, the semiconductor device and the cooler are molded by the mold resin. The intermediate member has a second surface that extends upward or downward relative to the first surface. The first surface is covered by the mold resin. The second surface is covered by a resin cover.