To provide a method of manufacturing an organic EL element, capable of preventing degradation of element characteristics and life of the organic EL element and improving various characteristics.

A first electrode 2 is formed on a substrate 1, on which a light-emitting medium layer 6 including an organic light-emitting layer 5 is laminated. Before or after baking or drying the light-emitting medium layer 6, the light-emitting medium layer 6 is exposed in an inert gas atmosphere to be preserved. The inert gas atmosphere is preferred to have an oxygen gas concentration of ≤1,000 ppm and a dew-point temperature of ≤-10°C. By providing a process of preserving for a given time period under an inert gas atmosphere, film quality is stabilized by aging, and emission efficiency, driving life, stabilization of driving voltage and characteristics are improved.