An injection molding resin-type printed wiring board having an electric circuit pattern layer formed integrally on the surface thereof and having reduced warpage. In the printed circuit board, the injection molding resin includes a thermoplastic resin composition essentially comprising polyethylene terephthalate and containing a flaky inorganic reinforcing material. The inorganic reinforcing material comprises single-substance fine mica flakes or a mixture of fine mica flakes and short glass fibers.