A guiding surface expanding to the outer circumferential side from the upstream side toward the downstream side is formed on the support section, a guided surface expanding to the outer circumferential side from the upstream side toward the downstream side is formed at an end portion on the outer circumferential side of the shielding member, and the shielding member covers a gap between the disc and the turbine blade in the fitting section in a state in which the guided surface abuts against the guiding surface at least when the disc is rotationally driven.