Fuel cell system

A fuel cell system includes a fuel cell (1), a reformer (2A), a source gas passage (6), a gas conveying source (60), a desulfurizer (100, 200), a sensor (510) detecting a physical quantity related to a dew point or a humidity of the source gas supplied to the desulfurizer, and a control portion (100X) informing maintenance information related to a maintenance of the desulfurizer on the basis of a first physical quantity (A, A1, A2) related to a cumulative operation time for the fuel cell system from a reference timing and a second physical quantity (B, B1, B2) related to a cumulative operation time from the reference timing during which the source gas having a dew point equal to or higher than a predetermined level or having a humidity equal to or higher than a predetermined level is supplied via the source gas passage, where the first physical quantity and the second physical quantity have physical quantities of the same unit.