Abstract: A muffler is received in a passage of an end member connected to a handle of the staple gun and a fitting extends from the end member so as to be connected to a hose. The muffler includes a tubular body and a plurality of plates extend from an end of the tubular body. The plats extend toward an interior of the handle and form a bullet-head-shaped arrangement. Gaps are defined between the plates and become smaller when air goes outward from the handle so as to reduce noise.