To control the size of a microlens by forming a fluidity controlling layer all over a low melting point glass layer and melting the low melting point glass layer by heating to form a microlens.

A diffusion preventing layer 2 is formed on a supporting substrate 1, and a low melting glass layer 3 is formed thereon. A photosensitive resist coating film 4 is applied to form a resist pattern 5. The pattern is used as a mask for etching to form grooves 6 in the low melting point glass layer 3. Then a fluidity controlling layer 8 is formed all over the low melting point glass layer 3. As for the fluidity controlling layer 8, a photosetting or thermosetting resin which can be ashed at the calcining temp. of the low melting point glass is used. The substrate 1 is calcined at a temp. higher than the softening point of the low melting point glass layer 3 and lower than the softening point of the substrate 1. When the low melting point glass layer 3 flows by melting, the fluidity controlling layer 8 suppresses the layer 3 from spreading. The fluidity controlling layer 8 disappears by ashing and microlens 9 are formed.