In the case where a material containing an alkaline-earth metal in a cathode, is used, there is a fear of the diffusion of an impurity ion (such as alkaline-earth metal ion) from the EL element to the TFT being generated and causing the variation of characteristics of the TFT. Therefore, as the insulating film provided between TFT and EL element, a film containing a material for not only blocking the diffusion of an impurity ion such as an alkaline-earth metal ion but also aggressively absorbing an impurity ion such as an alkaline-earth metal ion is used.