A burner 1 for combustion chamber is provided with a cylindrical mixing portion 3 that mixes air for combustion (oxidizing agent) and fuel in the interior thereof and has one end 3a that opens to a combustion portion 2; a spray nozzle (fuel spraying portion) 5 that sprays fuel in the mixing portion 3, being disposed on another end 3b of the mixing portion 3; first blowing ports 6 that introduce the air for combustion to the mixing portion 3 to form a swirling flow with the fuel, being disposed to open to the inner wall of the mixing portion 3; and second blowing ports 7 that additionally introduce the air for combustion to the mixing portion 3, opening in a direction different from the first blowing ports 6 and being disposed further to the other end 3b side of the mixing portion 3 than the swirling flow. The burner for combustion chamber and combustion method of the present invention can shorten the flame length in the central axial direction by improving the combustion efficiency even during low loading and shorten the overall length of the burner for combustion chamber in the central axial direction.