To provide a combustor capable of reducing the generation of NOx per charged fuel, preventing the generation of combustion vibration and the generation of flashback, having reduced environmental load and preventing the combustor and a structure connected with the combustor from being broken by the vibration.

This combustor BS1 comprises a casing 1, a cylindrical premixing cylinder 2, a combustion cylinder 3 communicated with the premixing cylinder 1, an air inflow part 11 for supplying the air for combustion, an airflow introducing part 13 for introducing the airflow to the premixing cylinder 2 while changing the direction of airflow, a pilot nozzle 4 mounted on an axis of the premixing cylinder 2, and main premixing nozzles 5 extended approximately in parallel with the pilot nozzle 4, and mounted in the premixing cylinder 2 at equal center angle intervals. The main premixing nozzles 5 respectively have a downstream-side fuel injection pegs 53, a first upstream-side fuel injection peg 71a is mounted at an upstream side of the air inflow part, and a second upstream-side fuel injection peg 72a is mounted between the first upstream-side fuel injection peg 71a and the main premixing fuel injection peg 53.