A process for manufacturing an organic electroluminescent device which is provided with a first electrode formed on a substrate, a thin film layer which contains at least one luminous layer composed of an organic compound and formed on the first electrode, and a second electrode formed on the thin film layer and has a plurality of luminous areas on the substrate, which process comprises the step of forming a spacer having a height which is partially larger than the thickness of the thin film layer on the substrate and the step of patterning a shadow mask having reinforcing lines formed so that the lines can cross openings by vapor-depositing a deposit in a state where the shadow mask is closely adhered to the spacer layer. This process makes it possible to form a fine pattern with high accuracy under a wide vapor deposition condition without deteriorating the characteristics of an organic electroluminescent element and, in addition, to realize a high stability through relative simple steps without limiting the structure of the luminescent device.