An optical module which forms recesses in a sol−gel layer provided on the rear surface of a lens array substrate to provide the recesses with an optical fiber−fitting function, the module comprising a flat−plate lens array substrate having a plurality of micro lenses arranged on a lens−forming surface, and an aligning recess array having a plurality of optical fiber aligning recesses arranged, by molding using a molding die, in a material bonded to the surface, opposite to the lens−forming surface, of the lens array substrate so as match the respective center positions of the plurality of micro lenses, the module further comprising a plurality of optical fibers having respective tip ends thereof fitted and inserted into relative aligning recesses for bonding and fixing there.