PURPOSE: To prevent the yielding of bubbles in a bonding agent, by applying a resin film on the surface of a solid state image-pick up elements, mounting an optical filter on the film on the surface of the elements through the bonding agent, thereby flattening the irregularities on the surface of the element with the film.

CONSTITUTION: On a wafer, in which a plurality of solid state image pick-up elements in CCD constitution are formed, light sensitive resist liquid is spin- coated. Thereafter, a resin layer 5 is formed by a thermosetting process. The surface of an image pick-up element 3 is flattened with the resin layer 5. A color filter 1 is bonded to surface with a suitable amount of an ultraviolet-ray hardening bonding agent 2. The device is exposed to light and hardened. By flattening the surface of the image pick-up element 3 with the film of the resin 5, bubbles are not formed at the angle parts of wirings 31 on the surface part of the image pick-up element 3. The yield of distortion on the optical image that is inputted to the image pick-up element 3 is prevented. Thus the quality of the image pick up device is improved.