An immersion tank includes a tank main body configured to store a coolant, at least one first air bag that is provided in the tank main body, that is coupled to a bottom portion of the tank main body, that is able to be inflated toward an upper portion of the tank main body, and that is able to be deflated, from an inflated state thereof, toward the bottom portion, and a guide member that is provided outside the at least one first air bag in the tank main body and that is configured to guide the at least one first air bag during the inflation and the deflation of the at least one first air bag.