The present embodiment sufficiently ensures the ignition stability and the flame-holding property of an afterburner while suppressing a reduction in the efficiency of an aircraft engine. A flame holder is disposed directly downstream of an injection hole of a fuel injector in a liner. The flame holder comprises: a ring-shaped annulus flame-holding member which is provided on the inner circumferential surface of the liner and is capable of propagating a flame in the circumferential direction; and a plurality of radial flame-holding members which are radially disposed inwards of the annulus flame-holding member and are capable of propagating the flame in the radial direction. A guide ring is provided inwards of the radial flame-holding members, and a ring-shaped guide channel that guides a fuel-containing mixed gas in the downstream direction is formed between the outer peripheral surface of the guide ring and the inner peripheral surface of the annulus flame-holding member.