The fuel cell power generation system includes a fuel cell, a reformer, a carbon monoxide decreasing unit, a first raw material supply source, a first valve which is provided to a first raw material flow passage, a second valve which is provided downstream of the carbon monoxide decreasing unit, a second raw material supply source which supplies a raw material to the inside of a flow passage which is closed by the first valve and the second valve from downstream of the carbon monoxide decreasing unit, and a control unit which controls the first valve and the second valve, wherein the control unit, after the first valve and the second valve are closed, supplies the raw material fed from the second raw material supply source to the inside of the flow passage closed by the first valve and the second valve at the time of stopping the system.