Lesion positioner systems and, which perform positioning of a lesion A by moving a top board for allowing a subject to be placed thereon, set an isocenter of a diagnostic 3D imaging unit as a virtual isocenter at the time when a treatment table is in a 3D imaging diagnosis position, and positions the lesion A to the virtual isocenter, based on a three-dimensional diagnostic image in consideration of particle beam therapy. A treatment table moving mechanism moves the treatment table to the treatment position relative to the particle beam therapy system while maintaining states of the top board and the lesion positioner systems and at the time of positioning, thereby positioning the lesion A to the isocenter of the particle beam therapy system.
