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 to a first position to cover the needle point of the needle tube and a second position to expose the needle point of the needle tube. The restriction mechanism restricts the protector from moving again from the first position to the second position after the protector moves from the first position to the second position and further moves from the second position to the first position.
