A gas turbine combustor (6) includes a combustor liner (8), a flow sleeve (10) in which the combustor liner (8) is provided and an annular flow passage (11) formed between the combustor liner (8) and the flow sleeve (10), through which compressed air (2) flows. The flow sleeve (10) includes an internal-diameter changing portion (10c) diagonally connected to the flow sleeve (10) and an internal-diameter reducing portion (10b) connected to the internal-diameter changing portion (10c) and extending along the flow direction of the compressed air (2). The combustor liner (8) includes an annular protruding portion (20) annularly formed on an outer wall of the combustor liner (8) and protruding toward the flow sleeve (10). The annular protruding portion (20) is located at a position on the outer wall of the combustion liner (8), the position facing a connection position between the flow sleeve (10) and the internal-diameter changing portion (10c) or being at an upstream side of the position facing the connection position in the flow direction of the compressed air (2).
