To provide a hydrogen storage unit that can heat a storage container including hydrogen absorbing alloy with favorable thermal efficiency, and a fuel cell system provided with the hydrogen storage unit. The cell body of the fuel cell is provided with a fuel cell stack configured to react hydrogen and oxygen to generate electricity, and a stack cooling passage configured to cool the fuel cell stack by circulation of a heat medium. The hydrogen storage unit of the hydrogen supply unit of the fuel cell is provided with: a housing; a plurality of cylinders that are housed in the housing and include hydrogen absorbing alloy; and a temperature control member having a heat medium flowing through the temperature control member so as to heat or cool the cylinder.