The invention discloses a gas burner which comprises an ejector tube assembly, a burner base, an outer ring burner body and an inner ring burner body. The ejector tube assembly comprises auxiliary gas pipe connectors, auxiliary nozzles, auxiliary ejector tubes, first main gas pipe connectors, first main nozzles, first main ejector tubes, second main gas pipe connectors, second main nozzles and second main ejector tubes. The auxiliary gas pipe connectors, the auxiliary nozzles and the auxiliary ejector tubes are communicated with gas pipes, each auxiliary gas pipe connector, each auxiliary nozzle and each auxiliary ejector tube are sequentially communicated with one another, and the auxiliary ejector tubes are further communicated with a primary air inlet. The first main gas pipe connectors, the first main nozzles and the first main ejector tubes are communicated with the gas pipes, each first main gas pipe connector, each first main nozzle and each first main ejector tube are sequentially communicated with one another, and the first main ejector tubes are further communicated with a first main primary air inlet. Each second main gas pipe connector, each second main nozzle and each second main ejector tube are sequentially communicated with one another, the second main ejector tubes are further communicated with a second main primary air inlet, and the second main gas pipe connectors are communicated with the first main gas pipe connectors through main gas ducts and branch gas ducts. The outer ring burner body comprises an outer ring base and an outer ring fire cover, and two symmetrical gas mixing chambers are formed. The gas burner has the advantages of being reasonable in structure, small in airflow resistance, sufficient in combustion, high in thermal efficiency and little in discharged waste gas.