To prevent crystal of ice of moisture in material to be cooled from being increased in size to destroy a cell membrane in preserving material to be cooled such as food at a low temperature (a freezing temperature or lower).

This cooling storehouse includes an ultrasonic wave generator 31 for applying strong and weak ultrasonic waves toward the material 28 to be cooled, wherein in a temperature zone higher than the freezing temperature, the ultrasonic wave generator is operated to apply a weak ultrasonic wave toward the material to be cooled, and then the ultrasonic wave generator is stopped to lower the temperature of the material to be cooled below the freezing temperature. Subsequently, the ultrasonic wave generator is operated to apply a strong ultrasonic wave toward the material to be cooled to be quickly freezed.

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