PURPOSE:To spread a liquid resin, which is potted aud sealed, on the entire surface of the inside of a sealing frame surrounding an element mounting part and to prevent the outflow of the resin beyond the sealing frame, by forming the sealing frame with a thermosetting resin, whose surface layer part is coated with water repelling powder. CONSTITUTION:A thermosetting resin 3 is applied around the semiconduc-torelement mounting part of a circuit board 1 in a frame shape. water repelling powder 4 is sprayed on the surface, heated and hardened. Thus a sealing frame 20 is formed. A semiconductor element 8 is die-bonded to the element mounting part. The pad of the element 8 is bonded to a pattern 5 of the board 1 with with 9 such as gold wire. A liquid resin is potted and sealed in the inside of the sealing frame 20. The resin is heated and hardened. For the thermosetting resin 3 forming the skelton of the sealing frame 20, epoxy resin, phenol resin, melamine resin and modified resin thereof are used. For the water repelling powder 4, the granule body of fluorine based resin or silicon based resin is used.