PURPOSE: To make possible the fitting/detaching of an iron core in a channel type induction heating device in a tundish for continuous casting on a tundish transferring truck.

CONSTITUTION: The iron core is divided vertically, and cored disk springs 22 for holding the necessary pushing force on the joining surface between the upper and the lower iron cores, fastening bolt 19 for fastening a lower iron core side bracket 15 and a movable plate 20 and fastening bolt 19 for fastening a tundish side bracket 18 and the lower iron core side bracket 15 are arranged in the lower iron core. Further, a torsion spring 23 for releasing the tension at the time of releasing the fastening bolt 19 and turning the bolt head by 90° with the spring force is arranged. By this method, the lower iron core can be set on the tundish transferring truck, and the workability of fitting/detaching the lower iron core is improved, too. As the number of spare lower iron cores is reduced and the fitting/detaching device for lower iron core is unnecessary in a maintenance field, the maintenance cost of the tundish can drastically be reduced.