A combustor comprising: a nozzle, having a rod-shaped portion centered on a burner axis (Ab), that sprays fuel; a burner cylinder, having a cylindrical shape surrounding an outer circumference of the nozzle; and an outside flow path cylinder, surrounding an outer circumference of at least a downstream end portion of the burner cylinder, that forms, between an outer circumferential side of the burner cylinder and an inner circumferential side of the outside flow path cylinder, a purge air flow path along which air flows toward the downstream side, wherein the burner cylinder covers the outer circumference of the nozzle and a plurality of revolving plates are provided, each of the revolving plates extending from the outer circumference of the nozzle in a direction including a radial direction component, and being connected to an inner circumferential surface of the burner cylinder, so as to cause the air to swirl around the burner axis (Ab); and a tapered surface (50, 51, 51a, 51b, 51c, 51d, 52) is formed in the downstream end portion of the burner cylinder such that a plate thickness of a burner cylinder-forming plate that forms the burner cylinder gradually thins as the burner cylinder-forming plate extends toward the downstream side, characterized in that a tapered surface formation width (t1, t2, t3, t4, t5) of the tapered surface (50, 51, 51a, 51b, 51c, 51d, 52) in a plate thickness direction is no less than half a plate thickness (t) of a part of the burner cylinder-forming plate where the tapered surface (50, 51, 51a, 51b, 51c, 51d, 52) is not formed, and in that a spraying hole for spraying the fuel is formed in a part midway along the nozzle in the axial direction (Da) along which the burner axis (Ab) extends; in that the plurality of revolving plates are provided near a location where the spraying hole is formed in the nozzle; and in that compressed air flowing into the burner cylinder at an upstream side thereof and fuel sprayed from the main nozzle are mixed in the main burner cylinder and form a premixed gas PM which is jetted from the downstream end of the main burner cylinder. a nozzle, having a rod-shaped portion centered on a burner axis (Ab), that sprays fuel; a burner cylinder, having a cylindrical shape surrounding an outer circumference of the nozzle; and an outside flow path cylinder, surrounding an outer circumference of at least a downstream end portion of the burner cylinder, that forms, between an outer circumferential side of the burner cylinder and an inner circumferential side of the outside flow path cylinder, a purge air flow path along which air flows toward the downstream side, wherein the burner cylinder covers the outer circumference of the nozzle and a plurality of revolving plates are provided, each of the revolving plates extending from the outer circumference of the nozzle in a direction including a radial direction component, and being connected to an inner circumferential surface of the burner cylinder, so as to cause the air to swirl around the burner axis (Ab); and a tapered surface (50, 51, 51a, 51b, 51c, 51d, 52) is formed in the downstream end portion of the burner cylinder such that a plate thickness of a burner cylinder-forming plate that forms the burner cylinder gradually thins as the burner cylinder-forming plate extends toward the downstream side, characterized in that a tapered surface formation width (t1, t2, t3, t4, t5) of the tapered surface (50, 51, 51a, 51b, 51c, 51d, 52) in a plate thickness direction is no less than half a plate thickness (t) of a part of the burner cylinder-forming plate where the tapered surface (50, 51, 51a, 51b, 51c, 51d, 52) is not formed, and in that a spraying hole for spraying the fuel is formed in a part midway along the nozzle in the axial direction (Da) along which the burner axis (Ab) extends; in that the plurality of revolving plates are provided near a location where the spraying hole is formed in the nozzle; and in that compressed air flowing into the burner cylinder at an upstream side thereof and fuel sprayed from the main nozzle are mixed in the main burner cylinder and form a premixed gas PM which is jetted from the downstream end of the main burner cylinder.