To provide a low NOx burner for liquid fuel which reconciles suppression of generation of NOx with improvement of combustibility.

The burner is provided with a combustion chamber 4 for performing combustion of flames, an air supply pipe 1 for sending combustion air to the combustion chamber, an air swirling chamber 2 which is provided at the end of the air supply pipe with its opening being at the combustion chamber side and being provided with air inflow ports 5 at the side adjacent to the opening for swirling therein the air that has flowed through the air inflow ports 5, a fuel-air swirling chamber 3 which is provided in the chamber 2 with its opening at the combustion chamber side and provided with air inflow ports 6 at the side adjacent to the opening for swirling therein the air that has flowed through the airflow ports 6 for mixture with fuel, and a fuel nozzle 7 for injecting liquid fuel to the fuel-air swirling chamber. The swirling flow of the air-mixed fuel from the chamber 3 and the swirling flow of secondary air from the chamber 2 are transferred to the chamber 4 in order that swirling combustion is performed therein.