To prevent a coating agent applied to the surface of a needle tube from infiltrating the space between a needle hub and the needle tube, a syringe needle assembly and medication injection device are equipped with a needle tube (5) that has a needle tip (5a) capable of puncturing a living body and is covered with a coating agent on the surface of the tip end at the needle tip (5a), and a needle hub (6) that holds the needle tube (5) in a such a way that the needle tip (5a) of needle tube (5) is projected. Furthermore, the needle hub (6) has a through hole (21) through which the needle tube (5) passes, and a discharge hole (23) that extends from the through hole (21) to the outer surface of the needle hub (6), and discharges any coating agent that infiltrates the inside of the through hole (21).
