Patent ID: 7686784

Claim:
A disposable syringe, comprising: a cylinder having both ends open; an adapter tube inserted into one side of the cylinder in substantially airtight contact with an inner circumference thereof; an injection liquid outlet tube at the fore end of the adapter tube; a needle held by a syringe needle holder coupled to the injection liquid outlet tube; an insertion tube at least partially inserted into the adapter tube, the insertion tube having a first connecting part formed at an aft end of an inner circumference thereof; a pressurization part inserted into and received by the injection liquid outlet tube and configured to pressure at least a tip of the needle against an inner surface of the cylinder when the needle is fully retracted into the cylinder and the pressurized part is inserted into the adapter tube, wherein the pressurization part has a projection part on an outer circumference thereof which directly contacts the first connecting part of the insertion tube when the pressurization part is inserted into the injection liquid outlet tube and also directly contacts the first connecting part when the substantially airtight contact is released between the cylinder and the adapter tube when the needle is fully retracted into the cylinder in a manner such that the pressurization part is still received by the injection liquid outlet tube.