PURPOSE: To perform drying in a short time without impairing a hose by connecting a dehumidifier to a dry air diffuser in a drying room, blowing off dehumidified air in the drying room, and directly passing part of the dry air to the hose.

CONSTITUTION: The door of the drying room 1 is opened, and the coupling of a wet hose after use is fitted in and connected to a coupling 5 for hose provided at the drying room 1. After setting the hose, the door is closed, and the dehumidifier 6 and a blast fan 7 are started up. Then the dry air is blown off from the dry air diffuser 3 to the drying room via a blast chamber 8. The dry air is directly blown off from a connected coupling 5 for hose to the inside of the hose, and the dry air is blown off from an open diffuser 4 whose diffuser is opened to the inside of the drying room 1. The air circulating the drying room 1 is exhausted from a wet air exhaust port 9, and is returned to the inlet port 11 of the dehumidifier 6 via a pipe 10 for wet air return.