There is provided a caulking bolt which can be fastened by a general nut even when used to fix thin plates to each other, and which can also provide fitting strength similar to that of conventional products. The caulking bolt includes a head part and a shaft part, and has a non-circular, flat, rotation preventive protrusion formed on a seat surface of the head part. Also, the upper end of a normal complete thread part formed in the shaft part is brought close to the seat surface of the head part with a distance of 3 pitches or less, and an incomplete thread part formed at the portion of 3 pitches or less is used as a stopper part into which a metal flows when the caulking bolt is driven into a metal plate.