Assembly of needle holder and barrel of safety syringe

The present invention relates generally to a safety syringe, and more particularly to an improved assembly of needle holder and barrel of the safety syringe. A safety syringe comprises a barrel having a retaining block disposed in the receiving hole, an initial stop portion and a final stop portion disposed in the end edge thereof, and a rotation resisting portion; a needle holder disposed in the barrel, and having a retaining groove and communicating with a port, a rotation stopping rod corresponding between the initial stop portion and the final stop portion of the barrel, overcoming portion capable of passing the rotation resisting portion of the barrel; and a plunger capable of catching and turning the needle holder. As the plunger is not engaged with the needle holder, the retaining groove of the needle holder confines the retaining block of the barrel. When the plunger is engaged with the needle holder which is turned, the overcoming portion of the needle holder overcomes the rotation resisting portion of the barrel, thereby enabling the port of the needle holder to be opposite in location to the retaining block of the barrel, so as to enable the needle holder to be drawn backwards.