Fuel cell system and desulfurization unit for the same

A desulfurization unit for a fuel cell system (400) includes a first desulfurizer (100) arranged in a temperature environment ranging from 50 °C to 200 °C and accommodating a desulfurizing agent including a porous material serving as a base material, the desulfurizing agent exerting a desulfurization effect in a normal temperature range, the first desulfurizer (100) adsorbing a sulfur compound included in a source gas in the temperature environment ranging from 50 °C to 200 °C when the source gas having a low dew point is supplied through a source gas passage (500) to the first desulfurizer (100) and when the source gas having a high dew point is supplied through the source gas passage (500) to the first desulfurizer (100).