PURPOSE: To automatically adjust the temperature and relative humidity of ambient fluid for a humidification and hot storage unit.

CONSTITUTION: The temperature and relative humidity of fluid are automatically adjusted by circulating the ambient fluid of storage room in an air channel 2 of ambient fluid adjustment unit 1. To the air channel 2, heaters 12 and 13, and a humidifier 20 are attached, and the air channel 2 functions by an arithmetic means to detect the temperature and relative humidity of fluid, and calculate the required heating output from the difference between the detected value and set value, and control means to automatically control the heaters 12 and 13, and humidifier 20 from the calculated value.