Syringe

A syringe comprising:

• a syringe barrel having an open distal-end portion and having an interior space to be filled with a liquid drug;
• a gasket fitted into the syringe barrel to seal in the liquid drug;
• an injection needle having a base-end portion adapted to pierce through the gasket at least during administration of the liquid drug;
• a plunger attached to the gasket and holding the injection needle;
• and
• a cover provided adjacent to a distal-end portion of the plunger,
• wherein the cover includes a plurality of first elastic engagement members for holding the injection needle, the first elastic engagement members being spaced apart from each other in a circumferential direction and capable of being deformed so as to be diametrically expanded,
• the cover is capable of moving in an axial direction relative to the injection needle between a state where a distal-end portion of the injection needle is housed within the cover and a state where the distal-end portion of the injection needle protrudes from a distal-end portion of the cover, and
• the elastic engagement members of the cover in the housing state and the injection needle engage so as to prevent the injection needle from being withdrawn from the elastic engagement members of the cover, and this engagement is released as the elastic engagement members are diametrically expansively deformed,
• characterized in that the plunger includes an integrated deformation-prevention part covering outer peripheries of the plurality of elastic engagement members so as to prevent the engagement from being released by the elastic engagement members being diametrically expansively deformed,
• wherein
• the plunger includes a plurality elastic engagement members for holding the infection needle, the plurality of second elastic engagement members being separated from each other in the circumferential direction and being capable of being diametrically expanded/deformed, and
• the deformation-prevention part is located closer to a distal end than the second elastic engagement members.