Steps for manufacturing an organic electroluminescent display device that can form an electrode pattern with high precision include forming a first insulating layer on a substrate and forming a first patterning layer, and forming a second patterning layer. The steps for manufacturing the organic electroluminescent display device further include forming a trench portion and forming an electrode layer on the second patterning layer and in the trench portion. In the step of forming the trench portion, an end of the first patterning layer exposed within the trench portion is etched to an outside more than an end of the second patterning layer exposed within the trench portion in a plan view, and in the step of forming the electrode layer, the electrode layer formed within the trench portion is isolated from the electrode layer formed outside of the trench portion.