A cooling facility for hot grain/lump material, in which air supplied from an air supply apparatus to plural carriages arranged along a circular carriage path so as to be movable, is used to cool the hot grain/lump material, wherein: the air supply apparatus includes a movable circular duct arranged along the carriage path and connected to each of the carriages through a connection air duct, a stationary circular duct arranged along the carriage path and fitted into the movable circular duct through a water sealing device so as to be freely movable, and a connection air duct closing mechanism (81, 91) for closing the connection air duct, wherein the movable circular duct and the stationary circular duct form a circular air path (25, 37); the water sealing device includes a circular water seal chamber (24a, 24b) arranged along the carriage path and a water sealing plate (34, 34b) having a lower end part thereof sunk in sealing water in the circular water seal chamber (24a, 24b); an atmospheric zone for stopping leakage of air in the carriages is provided in a predetermined position of the carriage path; and the cooling facility is configured to cause the connection air duct closing mechanism (81, 91) to close the connection air duct in the atmospheric zone and to cause the connection air duct closing mechanism (81, 91) to open the connection air duct in the zones (C,D) other than the atmospheric zone, the cooling facility being characterized in that: an upper space of the circular water seal chamber on a circular air path side is communicated with the circular air path on a movable circular duct side; and the circular air path on the movable circular duct side has no partition plate for partitioning the circular air path on the movable circular duct side in a circumferential direction so as to make the circular air path on the movable circular duct side communicate in the circumferential direction such that, in use, the pressure in the atmospheric zone and zones (C,D) other than the atmospheric zone is the same. the air supply apparatus includes a movable circular duct arranged along the carriage path and connected to each of the carriages through a connection air duct, a stationary circular duct arranged along the carriage path and fitted into the movable circular duct through a water sealing device so as to be freely movable, and a connection air duct closing mechanism (81, 91) for closing the connection air duct, wherein the movable circular duct and the stationary circular duct form a circular air path (25, 37); the water sealing device includes a circular water seal chamber (24a, 24b) arranged along the carriage path and a water sealing plate (34, 34b) having a lower end part thereof sunk in sealing water in the circular water seal chamber (24a, 24b); an atmospheric zone for stopping leakage of air in the carriages is provided in a predetermined position of the carriage path; and the cooling facility is configured to cause the connection air duct closing mechanism (81, 91) to close the connection air duct in the atmospheric zone and to cause the connection air duct closing mechanism (81, 91) to open the connection air duct in the zones (C,D) other than the atmospheric zone, an upper space of the circular water seal chamber on a circular air path side is communicated with the circular air path on a movable circular duct side; and the circular air path on the movable circular duct side has no partition plate for partitioning the circular air path on the movable circular duct side in a circumferential direction so as to make the circular air path on the movable circular duct side communicate in the circumferential direction such that, in use, the pressure in the atmospheric zone and zones (C,D) other than the atmospheric zone is the same.