Formed on a glass substrate is an EL element including an anode, an organic light emitting layer, and a cathode. A first protective film is formed on a surface of the EL element to cover the EL element through a dry process. A second protective film is then formed on a surface of the first protective film to cover the first protective film by using polysilazane through a wet process. Even if an uncovered portion is left in the first protective film owing to the existence of a foreign matter thereon, the second protective film covers the uncovered portion to avoid intrusion of oxygen or other gases, moisture, etc. into the EL element from the outside.