To simultaneously process a plurality of temperature processing cases by a method wherein a plurality of respectively independent temperature processing cases are provided in close vicinity, and when a large amount of food is frozen, the plurality of the temperature processing cases are temperature-set as a rapid freezer in response to the amount, and are used.

The basic usage configuration of a thermally processing device is divided into respective functions such as a rapid freezing chamber 1, a thawing chamber 2, a freeze storage chamber 3 and an ice temperature chamber 4, and for respective chambers, a temperature control is independently and individually possible for a range from a low temperature at which the freezing of foods is possible to a high temperature at which the ripening and the warm storage of food materials is possible, i.e., extending to a wide temperature range from -30°-+50°C. Therefore, the temperature of each chamber is set in response to the using purpose. For example, when a large amount of foods needs to be frozen at a time, the thawing chamber 2 is also used as the rapid freezing chamber 1, i.e., supply power to the Peltier element of the thawing chamber 2, is set the same as that of the rapid freezing chamber 1 to constitute the rapid freezing chamber 1 of a double capacity, and the freezing process is performed. The rapidly frozen foods are housed and stored in the freeze storage chamber 3 in order.