A method for manufacturing a semiconductor device that includes a housing, formed of a polyamide-series thermoplastic resin, and a semiconductor package sealed in the housing, which is formed of a thermosetting epoxy resin. The surface of the package is modified by UV-irradiation to have adhesive properties to polyamide. A plurality of connector terminals extend from the package and housing in parallel. A portion of the terminals is also sealed in the housing together with the package. Thus, the device is easily produced by insert molding and has excellent moisture resistance.