A solid-phase support, formed by binding a chain polymer at least to the surface, wherein the chain polymer is a block polymer comprising a first block constituted from repetitions of a hydrophilic structural unit and a second block constituted from repetitions of a structural unit having a reactive functional group, a content ratio of the number of moles “a” of the reactive functional group contained in the chain polymer and the number of moles “b” of the whole structural unit contained in the chain polymer, (a/b), is from 0.03 to 0.25, and a density of the chain polymer occupying the surface of the solid-phase support is 0.1 polymers/nm2 or more.