This invention provides a biomolecule modifying substrate comprising biomolecules selectively fixed to given regions thereon. The biomolecule modifying substrate comprises: a substrate at least comprising a first surface and a second surface; a first linker molecule comprising a hydrocarbon chain and a functional group capable of selectively binding to the first surface at one end of the hydrocarbon chain, which is bound to the first surface via such functional group; a second linker molecule comprising a reactive group capable of binding to the hydrocarbon chain of the first linker molecule, which is bound to the first linker molecule via a bond between the reactive group and the hydrocarbon chain; and a biomolecule bound thereto via the second linker molecule.