An injection needle assembly includes a needle tube, a needle hub configured to hold the needle tube, a protector, a biasing member, and a restriction mechanism. The restriction mechanism is configured to restrict the protector from moving from a first position to a second position again after the protector has moved from the first position to the second position and has further moved from the second position to the first position. Moreover, the biasing member is disposed close to a needle tip of the needle tube in an axial direction with respect to the restriction mechanism.
