A self-tapping including a normal thread (10) and a female screw molding thread (12) having a larger diameter than that of the normal thread (10), out of pitches of the normal thread (10) positioned in a head portion side from the female screw molding thread (12), any one pitch is set to be larger than other pitches. The self-tapping not only reduces driving torques but also improves fastening force, and thus can be applied to various workpieces made of the soft material as well as a hard material.