An impact-driven threaded nail includes a threaded portion with a lead angle of about 45°, the threaded portion being defined along an outer circumference of a nail shank that includes a first end defined as a pointed tip; and a head having a larger diameter than the nail shank, the head being integrally provided at a second end of the nail shank, wherein a tapered portion of the head on a back-surface side in continuation with the nail shank is defined in a pyramidal shape having one of regular pentagonal to octagonal cross-sections with a diameter decreasing gradually toward the nail shank, and the threaded nail is configured to be impact-driven and rotate into a mounting member when impacted.