Abstract: As a sealing structure for a syringe, a waterproofing film is adhered to the surface of a cap (6), a barrel (3) and a cylinder body (2) to cover fitting areas therebetween. The film is made of synthetic resin having a melting point higher than the temperature of flowing water vapor in post sterilization.As a sliding valve for a syringe, an inclined lip (24) is continuously protruded from the outer surface of a short cylindrical body (22). At the one end of the body, an annular lip (23) is formed. The inclined lip has a recess (34) for introducing a medicine liquid. The inclined lip may be formed in plural pairs of inverted , in plural stages, in plural strips in an axial direction, or in a shape to cross to form a sea slug wall. The sliding valve can be inserted with no inclination so that stagnant of air is not produced.