To provide a turbine combustor with a closed circuit cooling including an inside wall and an outside wall demarcating a combustion chamber, where a gap for passing a cooling fluid is formed between the inside wall and the outside wall, a cooling fluid introduction passage is opened to the gap and a cooling fluid discharge passage is provided for discharging the cooling fluid from the gap, improved to have a small radial expanding dimension.

The cooling fluid discharge passage has a duct-like discharge passage structure 8 extending along the axial direction of a combustor, and the discharge passage structure is interrupted by an inlet structure 4 of the cooling fluid introduction passage disposed between the discharge passage structures.