In one embodiment of the present invention, a degradable polymer having a peroxide bond therein is disclosed. The degradable polymer can be utilized in the fields of medicals or medical materials, can be applied to a DDS or gene delivery system, and can be used as a novel polymeric material or environmentally-friendly material. A polyperoxide, which is an alternating copolymer, has in a side chain thereof, a functional group (which is a substituent comprising a therapeutic molecule), a water-soluble substituent, or a biodegradable substituent.