To suppress drying of a food to a minimum limit and to realize deep freezing and storing of the food with high quality and good efficiency by stopping or low-speed operating a fan at an initial time of introducing the food and rapidly operating the fan during a period to freezing. SOLUTION: In a cabinet of the food deep freezer and a plurality of stages of food shelves 6 are vertically installed in a forward direction of a fan 4. A temperature sensor 8 for measuring a surface temperature of a representative food 7 is provided in the cabinet and its signal is input to a fan controller 9 for controlling the operation of the fan. A period from the introduction of the food into the cabinet up to freezing of the food to a predetermined temperature is divided into first and second periods of two and decided. The fan is controlled so that in the first period in which a saturated vapor pressure of a surface of the food is relatively high, the fan is stopped or low-speed operated and in the second period in which the saturated vapor pressure is lowered and the fan is operated at a high speed. Thus, an evaporation of a moisture from the surface of the food is suppressed to a minimum limit and deep freezing of the food of high quality can be realized.
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