Easily tearable fastener tape, method of producing the fastener tape, packaging bag with easily tearable fastener tape, and device and method for producing the packaging bag

An easily-tearable zipper tape that is attached to an inner surface of a package bag having an opening side, comprising:

• an engagement portion at which a male member and a female member are mated with each other;
• and belt-shaped bases provided continuously to the engagement portion of each of the male member and female member,
• at least one of the belt-shaped bases comprising:
• a main body on which the engagement portion is provided;
• a first projecting portion provided on the main body on a side adjacent to the opening side, the first projecting portion being thicker than the main body;
• a thin portion provided on the first projecting portion on a side adjacent to the opening side, and interposed between the first projectingportion and a second projecting portion, the thin portion being thinner than the first projecting portion and the main body;
• and
• the second projecting portion provided on the thin portion on a side adjacent to the opening side, the second projecting portion being thicker than the thin portion and the main body,
• wherein opposing surfaces of the first projecting portion and the second projecting portion respectively facing the inner surface of the bag body are substantially coplanarly positioned, and wherein the thin portion is recessed relative to the opposing surfaces to provide a level difference,
• the thin portion defining a tearing guide piece which is torn at a predetermined position when opening the bag.