portion 54 thus according to the embodiment air passing through the bypass passage is uniformly supplied to the combustor particularly to the combustor tail portion in the circumferential direction thereof so that the unevenness of the temperature distribution in the cross section of the combustor tail portion can be reduced as a matter of course in the above described second embodiment the arrangement of the supporting member in the annular space 55 is included within the scope of protection of the present invention fig1 is a longitudinal partial sectional view of a forth embodiment of a combustor according to the present invention in the forth embodiment a sleeve 70 is arranged substantially coaxially to the center axis of the combustor tail portion 50 between the outer wall of the combustor tail portion 50 and the inner wall of the annular scroll 60 therefore the sleeve 70 and the outer wall of combustor tail portion 50 are substantially parallel the length in the axial direction of the sleeve 70 is substantially identical to that of the annular scroll 60 as shown in fig1 a plurality of holes 71 are formed in the sleeve 70 a plurality of openings 51 are formed in the combustor tail portion 50 within the annular scroll 60 in the forth embodiment the plural openings 51 and the plural holes 71 are disposed in a staggered configuration the additional compressed air a entering the annular scroll 60 through the bypass passage 90 passes through the annular passage 61 and the hole 71 of the sleeve 70 and impinges on the outer wall of the combustor tail portion.