[Problem] To provide an injection needle assembly with which an injector mounted with a needle tube can be connected easily and a medicine injection apparatus using the injection needle assembly thereof. [Solving Means] An injection needle assembly 1 is an assembly used by being attached to an injector 52 including an injection barrel 54 filled with medicine and a needle tube 53, and is provided with a sticking needle tube 5 having a needle tip 5A to be stuck into a skin, a needle holding portion 21, an engagement portion 32 and a connection portion 14. The needle holding portion 21 holds the sticking needle tube 5 and a fit tube 35 of the engagement portion 32 is engaged with a needle hub 6 of the injection barrel 54. The connection portion 14 includes a luminal portion 41 in which there are arranged a proximal end 5B on the opposite side of the needle tip 5A of the sticking needle tube 5 and a needle tip (ejection port) 53A at the needle tube 53 of the injector 52, and the sticking needle tube 5 and the needle tube 53 communicate with each other in a liquid tight manner.
