An electrode plate suitable for use in an electro-optical device, such as a liquid crystal device, is formed by successively disposing on a substrate a first layer of a transparent conductor film, a second layer of molybdenum or a molybdenum alloy, a third layer of aluminum or an aluminum alloy, and a fourth layer of molybdenum or a molybdenum alloy. The laminate electrode structure is patterned by a photolithographic process, followed by removal of the photoresist with a peeling liquid, during which the fourth molybdenum layer functions as a protective film for the third al layer against the peeling liquid to prevent the formation of electrode defects.