A method of starting a gas turbine plant, which plant has at least one combustor including a primary combustion chamber into which primary fuel nozzles open and a secondary combustion chamber into which secondary fuel nozzles open, a compressor for supplying the combustor with compressed combustion air, and a gas turbine driven by the combustion gas generated in the combustor and adapted to drive a load such as an electric power generator. When the gas turbine is being accelerated to a rated speed or while the load is still below a normal load range, a fuel is supplied only to the primary fuel nozzle, whereas, in other loaded operation range, the fuel is supplied to both the primary and secondary fuel nozzles. Before the fuel supply to the secondary fuel nozzles is commenced, a part of the compressed air is bled through at least one air bleed pipe leading from the compressor and having an air bleed valve. The air bleed valve is controlled in such a manner that the opening degree thereof is maximized when the fuel supply to the secondary fuel nozzles is commenced and is progressively decreased in accordance with the increase of the load such as to become substantially zero when the load has been increased to the normal load range.