It is mainly intended to provide a sterilization bag which can be produced at a low cost, ensures the prevention of the sterilization bag damage and can exert an improved effect of sterilizing a medical instrument. A sterilization bag in which a space for holding the contents is formed by a first seal part whereby both sides of a first sheet member and a second sheet member and the bottom facing an opening are heat-sealed while leaving the opening, wherein the space for holding the contents has one or more stopper parts constructed by heat-sealing the first sheet member and the second sheet member in a specific planar shape.
