[Problem] The purpose of the present invention is to provide a syringe for use as a pre-filled syringe in which extended-period low molecular weight drug absorption and protein absorption is unlikely to occur. [Solution] The present invention is a syringe for use as a pre-filled syringe, said syringe comprising a plunger, which has a gasket attached to the tip thereof, and a syringe outer tube, which internally houses the plunger so as to be slidable, the syringe being characterised in that the surface of the gasket and the inner wall of the syringe outer tube have been surface modified by means of a polymer having bipolar ions.
