To effectively carry out cooling of even packaged food materials by using a vacuum cooling function.

This vacuum cooling unit is provided with a treatment tank 4 for dipping and holding the packaged food material 1 in liquid 2, a pressure reducing means 5 for reducing a pressure in the treatment tank 4, a pressure recovering means 6 for recovering the reduced pressure of the treatment tank 4, and an agitating means 7 for agitating the liquid of the treatment tank 4. The agitating means 7 is characterized by introducing gas into the liquid 2 of the treatment tank 4. The packaged food material 1 is held in the treatment tank 4 in a dipped state in the liquid 2, the pressure of the treatment tank 4 is reduced, and the liquid of the treatment tank 4 is agitated.