PROBLEM TO BE SOLVED: To provide a liquid fuel combustor structure in which lean premixed combustion can take place while suppressing NOx. SOLUTION: A premix burner is provided with a first air hole 51 for feeding third air in the outer circumference at the outlet of a first tubular ejection port 50 for feeding fuel and second air. First air is fed from an air swirler 10 such that the fuel particles intersect the air flow and premixed while being evaporated in an annular passage 45. The passage is enlarged abruptly at the outlet end before being coupled with a combustion chamber 20. The burner is combined with a burner 90 additionally provided with diffuse combustion in the center to constitute a single gas turbine combustor. According to the structure, a gas mixed uniformly with fine particle required for preevaporation premixed combustion is produced and a gas turbine combustor can be operated while suppressing NOx over a wide range.