The cost relating to a reduction in volume and storage of a waste resin including a radioactive nuclide is reduced. In an aspect of the invention, a volume reduction processing system 1000 is provided. The volume reduction processing system 1000 includes a radioactivity meter 102 that measures the radioactivity of a processing target resin, a volume reduction processing device 110 that carries out a heating process, and an oxidation process using oxygen plasma P on the processing target resin, and a process stopping point computation unit 180 that determines a process stopping point for carrying out a volume reduction process on the processing target resin with the volume reduction processing device as far as a volume reduction target value. The volume reduction processing device 110 stops at least one process of the heating process and oxidation process on the process stopping point being reached.