A main object of the invention is to provide a particle for medical use which has an excellent capability of fixing a target biologically active substance and has such chemical and physical stability that the particle is less dissolved or deteriorated in a washing step.The present invention has solved the above problem with a particle for medical use having a layer containing a polymer compound formed on a surface of a core particle, wherein the polymer compound is a polymer comprising at least repeating units derived from an ethylenically unsaturated polymerizable monomer (a) having a functional group for fixing a biologically active substance, wherein the polymer has a reactive functional group on at least one terminal side thereof.