Abstract: A gas turbine combustor comprising a combustor inner-pipe for forming a head combustion chamber and a rear combustion chamber having a diameter larger than a diameter of head combustion chamber. A combustor outer-pipe covers the combustor inner-pipe, and a fuel nozzle is disposed at an end part of the head combustion chamber for supplying fuel to said combustor inner pipe. A first group of ports are arranged for swirling and feeding air in an axial direction of the combustor inner-pipe. The first group of ports are around the fuel nozzle. A second group of ports for swirling and feeding air in a radial direction of said combustor inner-pipe are disposed in a side wall of the head combustion chamber near the fuel nozzle.