A manufacturing method for an organic electroluminescent device that includes an effectively optical area including display pixels for display and a dummy area surrounding the effectively optical area, the dummy area including dummy pixels not for display is provided. The manufacturing method includes coating a first composite material on a first portion in the effectively optical area, the first portion corresponding to one of the display pixels, and coating a second composite material separately from the coating of the first composite material, the second composite material being coated on a second portion of the dummy area, the second portion corresponding to one of the dummy pixels, the first composite material including a first organic electroluminescent material that is dissolved or dispersed in a solvent and the second composite material including a second organic electroluminescent material that is dissolved or dispersed in a solvent.