A gas turbine includes a compressor configured to compress air; a combustor configured to mix and combust fuel and compressed air compressed by the compressor; a turbine configured to obtain rotational power using combustion gas generated by the combustor; an inlet guide vane disposed at an intake of the compressor to adjust a flow rate of air flowing into the compressor; a bleed line configured to return a part of the compressed air pressurized in the compressor to the intake of the compressor; and an on-off valve disposed in the bleed line. When the output of the gas turbine increases, a preset maximum value limit of the inlet guide vane is corrected based on a valve opening degree command value of the on-off valve and a compressor intake temperature such that the gas turbine achieves a predetermined performance.