This paper presents a novel manipulation method utilizing dynamic deformation of a flexible body with a structural anisotropy. Employing a spiral flexible body, a dynamic underactuated manipulation using its various vibrational patterns is proposed. First, the orbit of the tip of flexible body for the vibrational input to its root is theoretically derived. Subsequently, for flexible bodies with and without the structural anisotropy, structural stiffness and vibrational orbit of the tip of body are analyzed. Through this analysis, the generation mechanism of the orbit change effect according to the input frequency is revealed. Finally, the proposed method is experimentally validated. After confirming the orbit change effect in a spiral flexible body, this effect is applied to an underactuated nonprehensile manipulation where three-Dof motion of an object is controlled by a single actuator.