A gas turbine includes a blade ring which faces blades from the outer side in a radial direction perpendicular to a turbine shaft, and a channel provided in the blade ring 1 and through which a cooling medium is flowed. The channel includes an inner channel formed in the blade ring 1, and a tubular outer channel which is connected to the inner channel, is disposed in an outer portion of the blade ring 1, and extends in a circumferential direction of the blade ring 1. The outer channel includes a plurality of fixing portions fixed to the blade ring 1 and a thermal stress absorbing portion disposed between the fixing portions adjacent in the circumferential direction and expandable and contractible in the circumferential direction.