A method of fabricating a microlens includes forming layer of photoresist on a substrate, patterning the layer of photoresist, and then reflowing the photoresist pattern. The layer of photoresist is formed by coating the substrate with liquid photoresist whose viscosity is 150 to 250 cp. A depth sensor includes a substrate and photoelectric conversion elements at an upper portion of the substrate, a metal wiring section disposed on the substrate, an array of the microlenses for focusing incident light as beams onto the photoelectric conversion elements and which beams avoid the wirings of the metal wiring section. The depths sensor also includes a layer presenting a flat upper surface on which the microlenses are formed. The layer may be a dedicated planarization layer or an IR filter, interposed between the microlenses and the metal wiring section.