A method is provided for manufacturing an electro-optical device, in which fine scratches or cracks can be removed by etching without damaging wiring, an electro-optical device, and an electronic apparatus. According to the method, a liquid crystal panel used in an electro-optical device is cut as a single product. Then, before an IC mounting step, in a state of the single product liquid crystal panel, a wet etching is performed on the cut faces and edges of the first and second substrates to remove fine scratches or cracks from the cut faces and edges of the substrates. At this time, wiring portions, IC mounting terminals, substrate mounting terminals, and alignment marks, which are formed on the protruding region, are covered with a protection layer.