PURPOSE: To set with high accuracy a set value of cooling control of a metallic plate by calculating a temperature at the time of start of cooling in plural points of the metallic plate by plural arithmetic elements, managing a connect- state of each arithmetic element, and adjusting the connection to a computer.

CONSTITUTION: By a computer 5, a heated metallic plate 42 is controlled so as to be cooled to a prescribed temperature. To this computer 5, a heat transfer calculating device(heat transfer calculating board) 10 is connected, by which based on input data containing a quality and a state, a temperature and an ambient temperature of the metallic plate 42, a temperature of the inside of the metallic plate 42 at the time of start of cooling is calculated by a heat transfer calculation. By plural arithmetic elements connected mutually, a temperature at the time of start of cooling in plural points of the metallic plate 42 is calculated, based on the input data. By a net master, the connecting state of the arithmetic elements is managed. By an adjusting means, the connecting to the computer 5 is adjusted. In such a way, the heat transfer calculation for calculating a cooling start temperature in plural points can be executed in parallel and at a high speed.