The steady-state response of damped disks rotating at a constant angular velocity was analyzed subjected to the external harmonic force at one point fixed in space. The distribution of the internal stress was obtained analytically from the equilibrium equation of radial force which was expressed by the space coordinate. The equation of motion of the rotating disk with the internal damping expressed by the complex Young's modulus was derived by use of Galerkin's method. The driving-point impedance, the mode shape, and the relationship among the angular velocity, the harmonic exciting frequency and the maximum amplitude have been calculated numerically.