A fuel cell system purifying apparatus comprising: a container that includes a first casing, a second casing, a plurality of accommodation chambers (15, 16, 17) which are formed between the first casing and the second casing by bonding of the first casing to the second casing, a communicating section through which one accommodation chamber of the plurality of accommodation chambers (15, 16, 17) communicates with another accommodation chamber of the plurality of accommodation chambers (15, 16, 17), a guide inlet which guides a fluid to flow into an inner portion of the plurality of accommodation chambers (15, 16, 17), and a guide outlet which guides the fluid in the inner portion to flow out; a purifying agent that is accommodated within the plurality of accommodation chambers (15, 16, 17), and purifies the fluid flowing through the plurality of accommodation chambers (15, 16, 17); and a purifying path where the fluid which is guided to flow into the purifying path via the guide inlet flows through till the fluid is guided to flow out via the guide outlet, wherein the purifying path is configured to be arranged to pass through the plurality of accommodation chambers (15, 16, 17) and the communicating section, the container includes welded sections in order to bond the first casing to the second casing, and the welded sections are provided by welding outer peripheries of the plurality of accommodation chambers (15, 16, 17) and of the communicating section, characterized in that one of the first casing and the second casing is provided with a recessed section (24, 25) that is disposed along the welded sections, and forms a space directly facing the other casing of the first casing and the second casing, between the welded sections of accommodation chambers (16, 17) of the plurality of accommodation chambers (15, 16, 17) which are adjacent to each other, and the recessed section (24, 25) exposes a bonding section that is positioned between the welding sections of the accommodation chambers (16, 17) which are adjacent to each other to the outside of the container throughout an entire periphery of the bonding section. a container that includes a first casing, a second casing, a plurality of accommodation chambers (15, 16, 17) which are formed between the first casing and the second casing by bonding of the first casing to the second casing, a communicating section through which one accommodation chamber of the plurality of accommodation chambers (15, 16, 17) communicates with another accommodation chamber of the plurality of accommodation chambers (15, 16, 17), a guide inlet which guides a fluid to flow into an inner portion of the plurality of accommodation chambers (15, 16, 17), and a guide outlet which guides the fluid in the inner portion to flow out; a purifying agent that is accommodated within the plurality of accommodation chambers (15, 16, 17), and purifies the fluid flowing through the plurality of accommodation chambers (15, 16, 17); and a purifying path where the fluid which is guided to flow into the purifying path via the guide inlet flows through till the fluid is guided to flow out via the guide outlet, wherein the purifying path is configured to be arranged to pass through the plurality of accommodation chambers (15, 16, 17) and the communicating section, the container includes welded sections in order to bond the first casing to the second casing, and the welded sections are provided by welding outer peripheries of the plurality of accommodation chambers (15, 16, 17) and of the communicating section, characterized in that one of the first casing and the second casing is provided with a recessed section (24, 25) that is disposed along the welded sections, and forms a space directly facing the other casing of the first casing and the second casing, between the welded sections of accommodation chambers (16, 17) of the plurality of accommodation chambers (15, 16, 17) which are adjacent to each other, and the recessed section (24, 25) exposes a bonding section that is positioned between the welding sections of the accommodation chambers (16, 17) which are adjacent to each other to the outside of the container throughout an entire periphery of the bonding section.