A premixed combustion burner for a gas turbine can efficiently premix fuel and air to produce fuel gas having a uniform concentration, while reliably achieving prevention of flash back by making the flow rate of fuel gas substantially uniform. The premixed combustion burner for a gas turbine has a fuel nozzle, a burner cylinder arranged so as to surround the fuel nozzle and form an air passageway between itself and the fuel nozzle, and swirler vanes that are arranged along an axial direction of the fuel nozzle in a plurality of positions around the circumferential direction of an outer circumference surface of the fuel nozzle. The swirler vanes gradually curve from an upstream side to a downstream side to spin the air traveling within the air passageway from the upstream side to the downstream side. A cutaway section is provided in a rear edge section on an inner circumference side of the swirler vanes.