PURPOSE: To enable adhesion of a substrate for an optical disk which allows transmission of UV rays and a substrate for an optical disk which allows trans mission of only the visible rays by using a high-sensitivity photosetting type adhesive.

CONSTITUTION: Adhesion of an optical disk is executed by applying the photosetting type adhesive consisting of a radical polymerizable vinyl compd., α-diketone, and the sensitizer expressed by formula on the surface to be adhered, press welding two sheets of substrates and irradiating surfaces to be adhered with light. The adhesion is so executed that the bubbles to highly hinder the radical polymn. are not present in the adhesive at this time. Any irradiation source for light is usable, insofar as the irradiation with an effective quantity of light is possible. General irradiation sources, i.e., carbon arcs, fluorescent lamps, incadescent lamps, etc., are usable.