ADAPTOR AND BLOOD COLLECTING INSTRUMENT

PURPOSE:To mount a syringe on an outer cylinder of a holder easily and accurately by arranging a first fitting section on the tip side to be fitted into a fixed member of the outer cylinder of the holder and a second fitting section on the side of a base end to have the tip of the syringe fitted into while a tapered section with an inner diameter thereof decreasing gradually toward the second fitting section is formed adjacent to the second fitting section. CONSTITUTION:A first fitting section 21 is formed on the tip side of an adaptor 2 to be fitted into a fixed member 5 formed sticking into an internal bottom of an outer cylinder 4 of a holder and a second fitting section 22 is formed on the side of a base end to have a protrusion 11 of the outer cylinder 10 of a syringe fitted into. A tapered section 23 with an inner diameter thereof decreasing gradually toward the second fitting section 22 is formed at a position adjacent to the second fitting section 22 on the side of the base end from the second fitting section 22. An angle of taper for a center axis of the tapered section 23 is about 5-10 deg., especially about 5-8 deg. preferably. This enables operation easily and accurately in mounting the syringe 9 on the outer cylinder 4 of the holder.