Fuel cell system

A fuel cell system includes a source gas passage (6) including a first desulfurizer (100) that has a desulfurization performance relative to a source gas having a relatively higher dew point, and a second desulfurizer (200) that has the desulfurization performance relative to a source gas having a relatively lower dew point and the source gas having the relatively higher dew point. The desulfurization performance of the second desulfurizer relative to the source gas having the relatively higher dew point is lower than the desulfurization performance of the second desulfurizer relative to the source gas having the relatively lower dew point. The first desulfurizer (100), the second desulfurizer (200), and a flowmeter (300) are arranged at the source gas passage (6) in the aforementioned order from an upstream side to a downstream side of the source gas passage in a flow direction of the source gas.