A wire-bonding machine includes a main body, a fixture block, a mounting block, a gas supply tube, a cover-gas supply device, a capillary tool and an electrode. The fixture block is provided with a chamber defined therein and a central bore formed at one side wall of the fixture block communicating the chamber. The mounting block has a fixture member extending upwards for being mounted to the main body and an electrode clamping member extending downwards into the chamber of the fixture block. The cover-gas supply device has a continuous gas passage and an orifice defined therein. The protection gas flows in a steady flow field around the orifice in the continuous gas passage of the cover-gas supply device so as to result in better ball formation during the ball formation and ball-bonding process.