the fixing projections 45 be each disposed at the same position as a corresponding one of the positioning projections 66 of the double ended needle 2 around the axis of the double ended needle 2 the constituent material of the cover member 4 is not particularly limited for example the constituent material of the hub 6 described above can be used as that of the cover member 4 in this case the constituent material of the cover member 4 may be the same as or different from that of the hub 6 next an operational sequence for operating the double ended needle assembly 1 and operational states of the double ended needle assembly 1 will be described with reference to fig1 to 4 1 as shown in fig1 the double ended needle assembly 1 is previously attached to the spout 201 of the syringe 20 as described above in the initial state the cover member 4 is secured to the double ended needle 2 and covers the distal end needle tip 51 of the needle tube 5 in the initial state the positioning projections 66 of the hub 6 are each engaged with the recessed portion 731 of the support member 3 whereby the double ended needle 2 is positioned in this state the double ended needle 2 is in a not yet punctured state where the proximal end needle tip 52 of the needle tube 5 does not yet puncture the puncture portion 8 of the support member 3 thus the not yet punctured state can surely be maintained until the cover member 4 is operated 2 next from the state shown in fig1 the cover member 4 is gripped and displaced in the proximal end direction then the cover member 4 along with the double ended.