To improve the surge resistance of J-FET, a P-type epitaxial layer 2 and an N-type epitaxial layer 3 are formed on a P++-conductive substrate 1; N+-conductive source diffusion layer 4 and drain diffusion layer 5, and a p+-conductive gate diffusion layer 6 are formed in the N-type epitaxial layer 3; and a short-circuit preventing layer 8 of a reversed conduction-type diffusion layer is formed adjacent to the side walls of the source diffusion layer 4 and the drain diffusion layer 5. Having the constitution, the punch-through to be caused by surge voltage is prevented in the surface region of the device, and the surge resistance thereof is improved. Via the holes formed in a protective insulation film 9 on the surface of the device, a source electrode 10 connected to the source diffusion layer 4, and a drain electrode 11 connected to the drain diffusion layer 5 are formed on the surface side of the device. A gate electrode 12 is formed on the back of the substrate 1, and this is connected to the gate diffusion layer 6 via a contact diffusion layer 7 formed in the device.