PURPOSE: To improve fastening force and to uniformly cool a mold by making flat square shape of head part of a stud bolt for fastening a mold plate and a backup frame and securing the prescribed gap at between top surface of the head part and an inner face of recessed part in a water passage for cooling.

CONSTITUTION: The mold plate 1 arranging slits 2 in the inner face at the prescribed interval, is fitted to a backup frame 3 with the stud bolt 4a, and cooling water is circulated in the slits 2 to cool the mold 10 for continuous casting. The prescribed gap 14 is formed at between the top surface of flat square head part 41 of stud bolt and the inner face of recessed part, and as this gap is communicated with the existing slits, even at the place, where stud bolt exists, cooling of the mold plate is perfectly executed. Further, the fastening of stud bolt is intensely and surely executed with fitting of the flat square head part and the recessed part of mold plate.