The present invention provides a control device that includes a first temperature detection unit that detects a partition wall temperature of a tank main body in which liquefied gas is contained, and a second temperature detection unit that detects a temperature of a skirt that supports the tank main body. The control device further includes a temperature difference acquisition unit that acquires a temperature difference between the partition wall temperature detected by the first temperature detection unit and the temperature of the skirt which is detected by the second temperature detection unit, and a determination unit that determines whether or not a joint between the tank main body and the skirt is rapidly cooled by the liquefied gas on the basis of the partition wall temperature and the temperature difference.