An object of the present invention is to provide a syringe for prefilled syringe in which the adsorption of a low-molecular medical agent or a protein for a long term is precluded. In accordance with the present invention, the above-described object is achieved by a syringe for prefilled syringe including: a plunger in which a gasket is attached to a top; and a syringe barrel in which the plunger is slidably accommodated, wherein the surface of the gasket and the inner wall of the syringe barrel are subjected to surface modification with a polymer containing zwitterion.