Such a rotating blade body is supplied as can prevent not only local wear and deformation but also inadvertent vibration and can maintain cooling efficiency. A rotating blade body consists of a rotor disc 2 and rotating blades 1 which are assembled so as to extend from the outer circumference of the rotor disc 2 in a radial pattern, wherein blade root portions 10 of the rotating blades 1 are engaged into blade grooves 20 which are formed along a direction of a rotating shaft on an edge of the outer circumference of the rotor disc 2. Circulation spaces 25 for the cooling air are formed along the direction of a rotating shaft between the bottom-end portions 10a of the blade root portions 10 and the bottom portions 20a of the blade grooves 20. Pushing-up members 3 which push up the rotating blades 1 outward in a radial direction are inserted into the circulation spaces 25, maintaining circulation of the cooling air.