An injection needle assembly includes: a needle tube, a needle hub which holds the needle tube, a protector, a biasing member, a retaining member, and a restriction mechanism. The protector is movable between a first position at which the needle tip of the needle tube is covered and a second position at which the needle tip of the needle tube is exposed, the protector comprising an abutment piece. The restriction mechanism is configured such that, after the protector has moved from the first position to the second position and has further returned from the second position to the first position, the restriction member restricts the protector from moving from the first position to the second position again.
