In order to provide a compression and volume-reducing apparatus for infectious waste, which is capable of reliably preventing the release of infectious materials to the outside when compressing and reducing the volume of infectious waste such as medical waste, this compression and volume-reducing apparatus (1), which compresses and reduces the volume of infectious waste (W), which has been loaded into a container (2), using a compression plate (4) configured so as to be lowered and raised by a raising/lowering mechanism (5), is provided with one mechanism or a combination of two or more mechanisms as sterilization mechanisms (8, 14) for sterilizing infectious materials to be released from the infectious waste (W), said one mechanism or combination of two or more mechanisms being any of a bactericidal irradiation sterilization mechanism, an electrical discharge/plasma irradiation sterilization mechanism, a soft X-ray sterilization mechanism, a heat sterilization mechanism and a photocatalytic sterilization mechanism.
