A positioning structure of a plastic disk in a massaging device may include a massaging unit, a connecting unit and a locking unit. The massaging unit has a protruding block that has a through hole. One end of the connecting unit has a receiving space that is used to receive the protruding block, a fixed hole of the connecting unit aligned with the through hole, and a plurality of positioning slots circularly formed at outer periphery of the fixed hole of the connecting unit. The locking unit has a head portion and a tubular unit extending from the head portion, wherein the tubular unit of the locking unit passes through the through hole and fixed hole, and a screw is used to secure the tubular unit to connect the massaging unit and the connecting unit.
