FUEL CELL, FUEL CELL DEVICE, FUEL CELL MODULE, AND FUEL CELL APPARATUS

[Problem] A fuel cell capable of suppressing deformation resulting from reduction treatment, a fuel cell device, a fuel cell module, and a fuel cell apparatus are provided. [Solution] A fuel cell of the invention includes a fuel electrode layer (4) disposed on a solid electrolyte layer (3), and an interconnector (6) and an adjustment layer (9) which are disposed on the fuel electrode layer (4), the interconnector (6) expanding in a reduction atmosphere and the adjustment layer (9) shrinking in a reduction atmosphere, or the interconnector (6) shrinking in a reduction atmosphere and the adjustment layer (9) expanding in a reduction atmosphere. Accordingly, a fuel cell (1) capable of suppressing deformation resulting from reduction treatment can be provided.