Solid oxide fuel cell

Provided is a solid oxide fuel cell (SOFC), including: a fuel electrode (110) for allowing a fuel gas to be reacted; an air electrode (140) for allowing a gas containing oxygen to be reacted; an electrolyte film (120) provided between the fuel electrode (110) and the air electrode (140); and a reaction prevention film (130) provided between the air electrode (140) and the electrolyte film (120). The porosity of the reaction prevention film (130) is less than 10%, particularly preferably "closed pore-ratio" is 50% or more. The diameter of closed pores in the reaction prevention film (130) is 0.1 to 3 ¼m. The reaction prevention film (130) includes closed pores each containing a component (e.g., Sr) for the air electrode (140). This can provide an SOFC in which a decrease in output due to an increase in electric resistance between an air electrode and a solid electrolyte film hardly occurs even after long-term use.