An IGCC plant which can improve the power generation efficiency and which can suppress the emission of sulfur components and dust into the atmosphere is provided. The IGCC plant described above has a coal gasifier for converting pulverized coal to a syngas; an exhaust heat recovery boiler generating steam; a gas turbine system which is operated by the syngas and which supplies a combustion exhaust gas to the exhaust heat recovery boiler; a steam turbine system operated by the steam generated by the exhaust heat recovery boiler; a power generator connected to the gas turbine system and/or the steam turbine system; a desulfurization device for removing sulfur components from the combustion exhaust gas discharged from the exhaust heat recovery boiler; and a wet-type electric precipitator for removing sulfur components and dust.