The jig 1 is used for positioning an inner tube and a transition piece of a combustor for a gas turbine when assembling the combustor. The jig 1 has the alignment member 2 that is inserted into the transition piece when positioning the transition piece to determine an installation position of the transition piece. The alignment member 2 has an outer circumferential shape which is substantially the same as an inner circumferential shape of the transition piece.
