[Problem] To provide: a syringe needle assembly which is provided with a cap which can be used with increased convenience by the user because the cap is configured so that the cap can be easily removed and so that the breakage of the syringe needle can be optimally prevented during the removal of the cap a syringe provided with the syringe needle assembly and with a liquid container used together with the syringe needle assembly and a method for operating a cap which protects a syringe needle.[Solution] A syringe needle assembly (10) has a syringe needle (20) which is inserted in a living organism, a hub (40) which holds the syringe needle and which is mounted in a removable manner to a liquid container (60) in which liquid is contained and held, a protective cap (30) which is mounted to the hub so as to cover the insertion section (21) of the syringe needle exposed from the hub. The protective cap is provided with a receiving section (35) open from the bottom surface, which is disposed on the hub side, to at least one side surface continuing to the bottom surface, and the receiving section (35) can receive the syringe needle. The cap is provided so as to be movable to a side of the syringe needle while the syringe needle is located within the receiving section, and the cap is removed from the hub by moving the cap.Cette invention concerne un ensemble-aiguille pour seringue qui est équipé dun capuchon plus facile à retirer et donc moins susceptible de casser laiguille au moment de son retrait une seringue comportant lensemble-aiguille et un récipient contenant un liquide utilisé avec lensemble-aiguille et une méthode permettant de manipuler le capuchon qui protège laiguille.Lensemble-aiguille pour seringue (10) comporte une aiguille (20) à introduire dans lorganisme dun être vivant, un raccord (40) qui tient laiguille et qui est monté de manière amovible sur un récipient contenant un liquide (60), un capuchon protecteur (30) qui est monté sur le raccord et qui rec
