A method of thawing an object (21) in a frozen state placed in an interior of a container (10), in which an AC voltage which is 10V or higher and 5 kV or lower is applied to the object (21) in the frozen state to flow a current which is 1 μA or higher and 1000 mA or lower, through the object (21) in the frozen state, comprises the steps of: partially thawing the object (21) in the frozen state in such a manner that a temperature in the interior of the container (10) is controlled to cause the object (21) in the frozen state to be partially thawed while applying the AC voltage to the object (21) in the frozen state and stopping application of the AC voltage to the object (21) and preserving the object (21) while maintaining a state in which the object (21) partially thawed.
