A combustor includes a first tube which supplies fuel and air from an opening formed in a distal end thereof, and a second tube which is configured such that flames are formed on an inner circumferential side thereof by the fuel and the air and the distal end of the first tube is inserted into an inner circumferential side of a proximal end thereof. The first tube includes a first tube main body and a ring part forming the distal end of the first tube. The ring part has a main body of a tubular shape and a plurality of protrusions that are integrally formed with the main body on an outer circumferential surface of the main body and protrude radially outward. When viewed in an axial direction, the outer circumferential surface of the main body has a polygonal cross-sectional shape within a range within which the protrusions are formed.