PURPOSE:To obtain a lateral MOS transistor type Josephson element by a thick insulating film by oppositely arranging a superconductive layer onto a substrate through an insulating layer and switching a constantly conductive condition and a super conductive condition by a controlling conductor disposed onto the insulating layer. CONSTITUTION:In 24 is evaporated onto the substrate 22, and coated with an SiO2 film 26. A window 28 is opened to the superconductive metal In film 24 and the SiO2 film 26, and the insulating film 30 is formed onto an inner circumferential surface and the bottom of the window 28 through thermal oxidation. The film corresponds to a gate insulating film of an MOS transistor, and a gate electrode 32 is shaped onto the film. The Josephson element forms the MOS transistor while using the superconductors 24a, 24b at both sides of the gate electrode 32 as a source and a drain. Accordingly, the comparatively thick insulating film 5 Josephson element with approximately 700Angstrom is obtained, and the element can be integrated to a high degree.