HYDROGEN GENERATOR AND FUEL CELL SYSTEM

A hydrogen generator (100) includes: a hydrogen generating unit (1) configured to generate a hydrogen-containing gas by using a raw material gas; a hydro-desulfurizer (7) configured to remove a sulfur compound in the raw material gas supplied to the hydrogen generating unit (1); a first gas channel (5) through which the raw material gas supplied through the hydro-desulfurizer (7) to the hydrogen generating unit (1) flows; a recycle channel (10) through which the hydrogen-containing gas from the hydrogen generating unit (1) is supplied to the raw material gas in the first gas channel (5) located upstream of the hydro-desulfurizer (7); a raw material gas supply unit (6) disposed between the hydro-desulfurizer (7) and a meeting point where the first gas channel (5) and the recycle channel (10) meet; and a first on-off valve (8) disposed between the raw material gas supply unit (6) and the hydro-desulfurizer (7) to close when the hydrogen generator (100) stops.