FUEL CELL SYSTEM

A fuel cell system includes: a hydrogen generating unit that generates hydrogen-containing gas using fuel that contains hydrogen-containing fuel; a cell stack that performs power generation using the hydrogen-containing gas; a supply amount acquiring unit that acquires a supply amount of the fuel supplied to the hydrogen generating unit; a detecting unit that is disposed on an upstream side of the hydrogen generating unit so as to detect oxygen or nitrogen in the fuel; a correcting unit that corrects an error included in a value from the supply amount acquiring unit based on detection results of the detecting unit, and acquires the supply amount of the fuel including air; and a calculating unit that ealeulates an amount of the air contained in the fuel based on detection results of the detecting unit.