The injection needle assembly includes a needle tube, a needle hub, a main body portion, a connecting portion, and a biasing portion. The main body is movable to a first position where the needle tip of the needle tube is exposed while being separated from the needle tip of the needle tube, and to a second position which covers the needle tip of the needle tube. And in a 1st position, at least one part in a main-body part protrudes in the needle tip side of a needle tube rather than a contact surface.注射針組立体は、針管と、針ハブと、本体部と、連結部と、付勢部と、を備えている。本体部は、針管の針先から離間して針管の針先を露出させる第１の位置と、針管の針先を覆う第２の位置に移動可能となっている。そして、第１の位置において、本体部における少なくとも一部が接触面よりも針管の針先側に突出する。
