PURPOSE: To improve durability of a combustion gas throat of a combustion device main body by a method wherein a throat column is separately formed and inserted between two liners.

CONSTITUTION: A combustion device main body 5 includes a first liner 1A and a second liner 1B having a dilution port 6 on the downstream side of the first liner 1A, and a throat column 10, whose sectional area reduces toward the downstream side, is inserted between the first and second liners 1A and 1B.