To simplify the entire process in a fuel cell from inspection of hydrogen leakage up to detection of hydrogen leakage and identification/repair of a leakage position where the hydrogen leakage occurs.

A fuel cell device 10 includes: a fuel cell 15; fuel gas pipings 27, 28 to supply and exhaust fuel gas to contain hydrogen to and from the fuel cell 15; a fuel cell case 17 having observation windows 30 from which the inside thereof can be observed visually; a hydrogen detection coating film installed so as to cover surfaces of the fuel cell 15 and/or the fuel gas pipings 27, 28 housed in the fuel cell case 17, and having a substance which is discolored when it comes into contact with hydrogen; and reflecting parts which comprise surface parts of the fuel cell 15 and/or the fuel gas pipings 27, 28 housed in the fuel cell case 17, and by which the situation of portions is reflected, which cannot be viewed directly from the observation windows 30, so as to be visually recognized from the observation windows 30.