To enable inspected good products to be shipped and enable 100% inspection by pressurizing a product housed in a treatment container to a pressure exceeding an atmospheric pressure, keeping it for predetermined time and thereafter reducing the pressure at a time.
A flexible package 1 is received in a body 2a of a treatment container 2, and the treatment container 2 is sealed. Then compressed air produced by a compressor 3 is introduced into the treatment container 2 by opening an inlet valve 5 while monitoring a pressure gage 9 for pressurizing to an appropriately set pressure with strength of the container 2 or the like taken into consideration. After pressurizing, the inlet valve 5 is closed, and the pressurized state is maintained for a predetermined time. Thereafter, a vent valve 7 is opened to release the compressed air in the treatment container 2 to an atmosphere at a time to suddenly reduce the pressure. With such treatment, by utilizing a fact that no change occurs on a good product, while a defective flexible package 1 with leakage swells, they can be distinguished from each other.
KOGURE SHINZO
ITO TAKASHI