A temperature-responsive polymer (hydrated graft structure) layer (2) composed of acrylamide derivative or the like exhibiting sensitive temperature-responsivity is immobilized to a magnetic particulate (1) composed of iron oxide or the like with a covalent bond. Further, an anticancer agent (3) is dispersed in the temperature-responsive polymer (2). The anticancer agent is ionically bonded to the temperature responsive polymer (hydrated graft structure).
