To provide a freezer capable of preventing and suppressing deterioration of quality of food while suppressing electric power consumption, and promptly carrying out freezing.

The freezer 10 has a magnetic field generator 2 applying a magnetic field to a freezing object 5 and changing its magnetic field intensity with lapse of time, and a magnetic field controller 3 controlling generation of the magnetic field and magnetic field intensity from the magnetic field generator 2. When a temperature near a surface of the freezing object 5 is Ts(°C), and an estimate of a temperature near a center part of the freezing object 5 is Tc(°C), the magnetic field generator 2 is controlled so that the magnetic field from the magnetic field generator 2 is stopped or attenuated when Tc-Ts becomes 30°C or lower. The temperature Tc near the center part of the freezing object 5 is estimated on the basis of parameters such as weight and thickness of the freezing object 5.