NOVELTY - A hydrogen gas station comprises: (i) reformer configured to generate hydrogen-rich reformed gas through reforming reaction of organic compound; (ii) gas supply port (35) configured to communicate with gas supply pipe (2) to supply reformed gas to fuel cells; and (iii) gas recovery port (36) configured to communicate with gas recovery pipe (6) to receive off gas containing hydrogen unconsumed from fuel cells, hydrogen gas station configured to consume off gas.    USE - For a fuel cell system (claimed).    ADVANTAGE - The hydrogen gas station and fuel cell system are configured to recover an off gas containing hydrogen unconsumed in fuel cells, and exhausted from fuel gas outlets of the fuel cells, to efficiently utilize the off gas. It is possible to stably supply the reformed gas and stably recover the off gas according to the power generation amount of each fuel cell, thus convenience of the distributed fuel cell system is improved, and operation efficiency is improved. Since the value of the off gas, which is the fuel source is properly estimated, a correct amount of hydrogen consumption in the fuel cell is calculated.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for:    (1) a fuel cell system (100) comprising a hydrogen gas station configured, to generate a hydrogen-rich reformed gas through reforming reaction of an organic compound; fuel cells, each of which is configured to generate electric power using the reformed gas supplied from the hydrogen gas station; a gas supply pipe through which the reformed gas is guided from the hydrogen gas station to the fuel cells; and a gas recovery pipe through which an off gas containing unconsumed hydrogen from the fuel cells is guided to the hydrogen gas station; and    (2) a hydrogen gas rate accounting device (80), comprising a first flow rate sensor (31) configured to, for each of fuel cells, measure a flow rate of a hydrogen-rich reformed gas generated in a hydrogen gas station, and supplied to the fuel cells; and a second flow rate sensor (32) configured to, for each of the fuel cells, measure a flow rate of an off gas containing hydrogen unconsumed in each of the fuel cells; and a processor, which is configured to calculate an amount of hydrogen consumption in each of the fuel cells, based on the flow rate of the reformed gas measured by the first flow rate sensor, and the flow rate of the off gas measured by the second flow rate sensor, and to carry out hydrogen gas rate accounting based on the amount of hydrogen consumption.    DESCRIPTION OF DRAWING(S) - The figure is a view showing a construction of a distributed fuel cell system.    Gas supply pipe (2)    Gas recovery pipe (6)    First flow rate sensor (31)    Second flow rate sensor (32)    Gas recovery sub-pipe (33)    Gas supply port (35)    Gas recovery port (36)    Hydrogen gas rate accounting device (80)    Fuel cell system (100)