A method for freezing a frozen item (21) according to the present invention has: a step for controlling and keeping a temperature inside a container (10) to a predetermined freezing temperature and applying an AC voltage to the frozen item (21) in the container (10) in such a manner that a small amount of current (1 μA or higher but 1000 mA or lower) flows through the frozen item (21); and a step for freezing the frozen item (21) at the predetermined freezing temperature for a predetermined storage period or longer while the AC voltage is being applied to the frozen item (21) inside the container (10).
