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 reaction prevention film (130) includes two layers including one layer of a porous layer (131) having an interface with the electrolyte film (120); and one layer of a dense layer (132) having an interface with the air electrode (140). The dense layer (132) has a porosity of 5% or less and the porous layer (131) has a porosity of 5.1 to 60%. The porous layer (131) includes closed pores each having a diameter of 0.1 to 3 µm. The porous layer (131) includes closed pores each including a component (such as 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.