A rotating body includes a rotating body core, and a plurality of blades provided at an outer or inner circumference of the rotating body core at equal intervals in a circumferential direction, and connected circumferentially via an annular connection portion provided separately from the rotating body core. A resonance frequency under a two nodal diameter number mode of the rotating body is lower than or equal to a rotational secondary harmonic frequency with respect to a rated rotation speed. Where Nd represents an order of a maximum mistuned component among order components of circumferential distribution of mass, rigidity or natural frequency of the blades, arrangement of the blades satisfies Nd≥5, and has order components each having ratio less than 1/2, in which the ratio is obtained by dividing the order component by the magnitude of the component of the order Nd.