NOVELTY - A depurant container device for a fuel cell system introducing a gas-phased or liquid-phased fluid, comprises a first fluid passage forming member (300) forming a first fluid passage (305) through which the fluid flows; and a second fluid passage forming member (400) forming a second fluid passage (405) which is in communication with the first fluid passage via the opening.    USE - The depurant container device is used for a fuel cell system introducing a gas-phased or liquid-phased fluid (claimed).    ADVANTAGE - The depurant container device for a fuel cell system and a fuel cell system including the depurant container device, are readily manufactured and favorable for forming joining portions with a high sealing performance. The fuel or the water can be sufficiently purified by the depurant, for example, the desulfurization agent or the water purifier. Thus, an output of the fuel or the water which is not sufficiently purified by the depurant to a system provided at a downstream of an outlet port (e.g., a reformer, or a fuel cell) is restrained, and a reliability of the system in a long term is enhanced.    DETAILED DESCRIPTION - A depurant container device for a fuel cell system introducing a gas-phased or liquid-phased fluid, comprises an intermediate plate member (200) including a first surface and a second surface provided at opposite sides, and an opening for flowing the fluid in a U-shape between the inlet port and the outlet port; a first fluid passage forming member (300) forming a first fluid passage (305) through which the fluid flows; and a second fluid passage forming member (400) forming a second fluid passage (405) which is in communication with the first fluid passage via the opening. The first fluid passage forming member contacts the first surface of the intermediate plate to be joined to it by a joining portion (703, 704). The second fluid passage forming member contacts the second surface of the intermediate plate to be joined to it by the joining portion so that the depurant container device is sealed. An INDEPENDENT CLAIM is a fuel cell system, comprising a fuel cell to which an anode fluid and a cathode fluid are supplied for generating an electric power; a reforming portion forming the anode fluid by reforming a fuel using a water vapor; a fuel passage for supplying the fuel to be the anode fluid to the reforming portion; a desulfurizer provided at the fuel passage for containing a desulfurization agent which purifies the fuel by removing an odorant included in a fuel as the depurant; where the desulfurizer is constructed with the depurant container device for the fuel cell system above.    DESCRIPTION OF DRAWING(S) - The drawing shows a cross-sectional view of a desulfurizer.    Intermediate plate member (200)    First fluid passage forming member (300)    First fluid passage (305)    Second fluid passage forming member (400)    Second fluid passage (405)    Joining portion (703, 704)