To attain reliable jointing between optical materials, independently of the changes in the thermal environment while preventing bubbles from entering into the gap between the optical materials, even when the optical materials to be jointed are mutually different materials.

A jointing layer 4 present between optical materials 3, 5 and used for jointing the materials 3, 5 to each other is composed of an agglutinant layer and adhesive filled into the gap between agglutinant layer and at least one of the optical materials.