Syringe

摘要

A syringe has a tubular body provided at its front end portion with a portion for mounting an injection needle thereon and opens at its rear end portion so as to have a rear end opening. A gasket for sealing the rear end opening of the tubular body is slidably inserted into the tubular body. A plunger rod is detachably coupled with a rear end portion of the gasket through the rear end opening of the tubular body. A male screw is formed at a front end portion of the plunger rod and is circumferentially alternately divided into at least one male screw portion and at least one first recess portion. A female screw is formed on a rear end face of the gasket and is circumferentially alternately divided into at least one female screw portion and at least one second recess portion. A state where the male screw portion and the first recess portion of the male screw are, respectively, fitted into the second recess portion and the female screw portion of the female screw, the male screw is rotated relative to the female screw so as to be brought into engagement with the female screw such that the plunger rod is coupled with the gasket.