A combustor includes: a combustion liner having a combustion chamber formed therein; and a fuel injector mounted to a top portion of the combustion liner, and including a fuel injection member having a plurality of fuel injection annular portions and an air guide member including a plurality of combustion air annular portions that guide air for combustion. The fuel injection annular portions and the combustion air annular portions are arranged concentrically and alternately. The fuel injector injects fuel and air into the combustion chamber. Each of the fuel injection annular portions includes a plurality of fuel injection holes that are open in a radial direction thereof, and each of the combustion air annular portions includes a plurality of air guide grooves that are open in an axial direction thereof, and guide the air to the fuel jetted from the fuel injection holes.