To eliminate a fluid unstable phenomenon and to reduce power of a motor by starting the operation, after setting the opening of an air bleed valve by throttling the opening from the full opening in starting, full opening the air bleed valve on the way, and performing the operation so that the air bleed valve may be full closed at 90% of the revolutions, concerning a gas turbine start method.

An IGV and a variable stationary blade are set as shown in a figure (a), so as to have a prescribed opening and the revolution in the range of 0 to rating. As shown in figure (b), an air blood valve 5 is operated of to 52% of the revolution, an air bleed valve 8 is operated to 51% of the revolution, an air bleed valve 11 is operated up to 51% of the revolution, and then the valves are opened fully. When the revolution exceeds 90%, the valves are fully closed and operated to rating. Conventionally, the bleed valves are fully opened and operated until the revolution increases to 90%, and then fully closed. However, with the operation of this gas turbine, the waste amount of air to be discharged to the atmosphere is reduced, and power of a starting motor can be saved.