FUELL CELL SYSTEM

A fuel cell system (1) includes: a fuel cell (51) that generates electric power using reforming gas and oxidizer gas; an evaporating unit (32) that generates water vapor from reforming water; a reforming unit (33) that generates the reforming gas from a reforming raw material supplied from a supply source (Gs) and the water vapor supplied from the evaporating unit; a reforming gas supply pipe (54) that supplies the reforming gas to a fuel flow passage (51 a2, 51 b2) of the fuel cell; a combustion unit (35) that corresponds to a combustion space in which combustible gas led out from the fuel cell is burned between the evaporating unit, the reforming unit, and a plurality of lead-out ports (51a3, 51 b3) for the combustible gas; and a firing-up apparatus (38) that performs discharge to ignite the combustible gas and fire up the combustion unit.