Patent ID: 7393341

Claim:
A syringe barrel for an injection apparatus, the syringe barrel mounted on a cylinder holder that comprises a flange insertion groove with a flat front inner wall, the syringe barrel comprising: a tip at a front side of the barrel; a rear side of the barrel opposite the front side of the barrel; a flange having a front surface, wherein the front surface is a surface of the flange closest the tip, a rear surface opposite the front surface of the flange, and a projection on the rear surface thereof, said flange being adapted to be held by said flange insertion groove so as to fix the syringe barrel; the projection being formed such that when the flange is inserted in the flange insertion groove on the cylinder holder and mounted in a use position, a tip of the projection is compressed whereby the flange is fitted into the flange insertion groove and fixed, wherein the front surface of the flange which is just opposite the side of the projection touches the front wall of the groove when the flange is inserted into the flange insertion groove, wherein the projection and the flange together are capable of being inserted in the flange holding groove and the tip of the projection is capable of being compressed so as to press the flange against a front sidewall surface of the flange insertion groove in a use position; and wherein the projection has a narrower width toward the tip, whereby the projection is more deformed when compressed; said cylinder holder comprising: a flange insertion groove for holding the syringe barrel; and a concave portion formed on an inner wall surface of the flange insertion groove to be contacted with the rear surface of the flange of the syringe barrel; whereby, the concave portion is engaged with the projection on the rear surface of the flange when the syringe barrel is mounted in a use position.