A safety needle assembly includes a hub including a proximal end and a distal end, the proximal end being connectable to a syringe, a cannula, a collar, a protector, and a sheath sheath including an opening extending in a longitudinal direction along at least a part of the sheath, the opening being configured to house the cannula, a cannula fixing part configured to fix the cannula with respect to the sheath, the cannula fixing part comprising a plurality of wing walls extending in a longitudinal direction along at least a part of the sheath； an attachment part configured to rotatably support the sheath with respect to the collar such that the attachment part is rotatable to a position at which the cannula is housed in the opening of the sheath； and a guide rib including a locking protrusion configured to lock the cannula inside the opening.
