To provide a fluid machine provided with a guide blade ring having outer and inner cover bands capable of restricting leak loss to the minimum by holding the optimum interval in any operation condition.

Guide blade rings 14, 15 closed in a circumferential direction has self-carry type parts provided with reinforcement parts to reinforce parts to deformation in an axial direction of folding at positions of inner cover bands 16, 17. The guide blade rings 14, 15 have outer cover bands 18, 19 in the form of segments having at least three separation seams distributed in circumferential directions, and they are respectively positioned in a housing 13 using shaft bearing units 24, 25, 26, 27 capable of performing relative motion in a radial direction with relation to space. An air guide shell 30 is disposed between the housing 13 and the outer cover band 18, 19 of the guide blade ring 14, 15, and part of a cooling air current is supplied from an opening 31, 32 to the shaft bearing members 26, 27 toward the cover band 18, 19.