There is provided coal gasification unit including: a coal gasifier; a char recovery unit; flare equipment; an air flow rate adjustment valve and an oxygen supply flow passage that supply oxygen-containing gas to the coal gasifier; an inert gas supply flow passage that supplies nitrogen gas to an upstream side of the char recovery unit; and a control unit that controls a supply amount of the oxygen-containing gas and a supply amount of the nitrogen gas, in which the coal gasifier has a starting burner, and in which the control unit controls the supply amount of the nitrogen gas prior to starting combustion of starting fuel by the starting burner so that an oxygen concentration of mixed gas in which combustion gas generated by combustion of the oxygen-containing gas and the starting fuel has been mixed with the nitrogen gas becomes not more than an ignition concentration.