The present invention reduces the concentration of thermal stress on a burner. A gas turbine combustor receiving compressed air from a compressor, mixing the compressed air with a fuel, burning the mixture to generate a combustion gas, and supplying the combustion gas to a turbine. The combustor includes: an inner cylinder internally forming a combustion chamber; an outer cylinder covering the inner cylinder and forming a cylindrical outer circumferential flow path between the inner and outer cylinders to allow the compressed air to flow; and a burner mounted on an end of the outer cylinder, which is positioned on an opposite side to a turbine side, and facing the combustion chamber. The burner includes a cylindrical base frame including a cavity distributing the fuel, and fuel nozzles circularly arranged as viewed from the combustion chamber and connected to the cavity. When viewed from the combustion chamber, slits extending radially are formed in the base frame such that each separate the circumferentially adjacent fuel nozzles from each other.