An exhaust gas processing device (16) intermittently introduces anode off-gas from a fuel cell (12). The exhaust processing device (16) discharges the anode off-gas after diluting it with dilution gas. The exhaust gas processing device (16) includes a dilution container (25) and a partition plate (28), which divide the interior of the dilution container (25) into a first chamber (26) and a second chamber (27). The partition plate (28) has a clearance (29), which connects the first chamber (26) and the second chamber (27) to each other. The exhaust gas processing device (16) includes a discharge portion (32) provided in the first chamber (26), a dilution gas inlet portion (30) provided in the first chamber (26), and an anode off-gas inlet portion (31) provided in the second chamber (27).