PURPOSE: To readily sterilize a chemical agent with steam under a high pressure, by containing the chemical agent, such as physiological saline solution, in a self-supporting packaging bag having through-hole parts and a filter applied to the interior.

CONSTITUTION: Physiologically saline solution is contained in a self-supporting bag having through-holes formed in a drum wall member and inner surfaces of the through-holes covered with a waterimpermeable filter material having gas permeability of 5-1000sec/100cc air permeability and sterilized with steam at 100-150°C temperature for about 5-60min under a high pressure. Since the self-supporting bag capable of preventing fracture of a bag due to increase in internal pressure in the bag in sterilization is used, the bag is lightweight, disposable and readily handleable in transportation, etc. The self-supporting packaging bag consists of a synthetic resin film, such as polyethylene, having heat-bonding properties on the inner surface.