Patent ID: 8616413

Claim:
A syringe comprising: a syringe outer tube having a tubular shape to be filled with a liquid and provided with a spout through which the liquid passes at a distal end portion thereof; and a cap mounted to the spout, wherein the cap includes a cap main body which seals the spout in a liquid-tight manner, a ring-shaped mounting section which is disposed on a proximal end side of the cap main body and is mounted onto an outer circumferential portion of the spout, and a breaking section which links the cap main body and the mounting section and a link is releasable by breaking, one of an inner circumferential portion of the mounting section and the outer circumferential portion of the spout is formed with at least one projection, while the other is formed with a groove into which the projection is inserted and which has an inclined section that is inclined in relation to an axis of the other, and when the cap is rotated relative to the syringe outer tube around an axis of the syringe outer tube, the projection moves along the inclined section of the groove, whereby the mounting section is displaced in a proximal direction relative to the spout and the cap main body, and the breaking section is pulled in the same direction to main body thus separated from the mounting section cannot be mounted again onto the spout.