To provide a method for working to accurately manufacture a microlens having a curved surface.

At a first step, photosensitive resin material 30 on a base 20 is exposed by using a first mask 10 having a circular light shielding pattern 11, and an exposed part is removed to form a cylindrical lens substrate 31 on the base 20. At a second step, the substrate 31 is exposed to introduce a light obliquely by using a second mask 40, and repeatedly exposed while altering a light introducing angle, and a periphery of the substrate 31 is gradually removed to form a convex polygonal protrusion above near a shape of the microlens on the base 20. At a third step, the protrusion on the base 20 is heated to be contracted to form a periphery of the protrusion in a curved surface.