A moving blade fastening construction comprising moving blade fingers formed in the moving blade root portion and rotor wheel fingers formed in the rotor wheel root portion and arranged so that the fingers of the moving blade are inserted in spaces defined between the fingers of the rotor wheel, thereby to provide at least two engaging portions radially spaced from each other. An average thickness of the moving blade finger is larger than that of the rotor wheel finger which is made of material larger in Young's modulus than the moving blade fingers, whereby stresses induced in the moving blade root portion are made uniform.