The rotor structure is provided with a rotation shaft body in which a blade groove is formed at an outer circumference part, and extends in a circumferential direction of the axis line, and a plurality of blade bodies which are arrayed in the circumferential direction at the outer circumference part of the rotation shaft body, wherein a blade fixing piece is installed so as to be a positioned between at least one set of adjacent two blade bodies in the circumferential direction inside the blade groove, a projected part is formed at where either an opening wall part or the groove opening side of the blade groove and the blade fixing piece, and a recessed part which is fitted into the projected part is formed at where the other one of them.