PURPOSE: To enable cooling by specific latent heat of vaporization due to pressure control of circulating air current without using cooling medium such as cooling water in a cooling step in an air current type treating apparatus.

CONSTITUTION: In a temperature-raising and constant temperature retaining step of treating fluid, a fabric is treated with gas-liquid mixed fluid or only liquid fluid and in a cooling step, the fabric is treated by pressure control of circulating air current. A pressure sensor 30 for detecting pressure in an air current type treating apparatus and a pressure control valve 32 for cooling control connected to the air current type treating apparatus are provided and a high-temperature discharge valve 12 connected to a residence tank and the pressure controlling valve 32 are controlled based on signal from a pressure sensor 30 by a control part 33 and pressure in the treating apparatus is gradually reduced.