To provide a fuel cell system configured to, at the time of starting the fuel cell system, purge gas other than fuel gas from the fuel electrodes of a fuel cell stack in a short time. A fuel cell system comprising: a fuel cell stack, an ejector set, a fuel gas supplier, a circulation flow path, a mixed gas supply flow path, a pressure detector which detects pressure information of a fuel electrode side of the fuel cell stack, a fuel off-gas discharger which discharges the fuel off-gas, in which a concentration of the fuel gas is a predetermined concentration or less, to the outside, and a controller, wherein the ejector set includes a first ejector and a second ejector in parallel, the first ejector being an ejector which supplies first mixed gas to the fuel electrodes of the fuel cell stack, and the second ejector being an ejector which supplies second mixed gas, in which a content ratio of the circulation gas is larger than the first mixed gas, to the fuel electrodes of the fuel cell stack.