A heat-dissipating apparatus has a cooling tube, a tubular conductor and a heat sink. The cooling tube has a body and an inlet and an outlet formed on the periphery of the body and communicating with an inner space of the body. The tubular conductor is mounted in the cooling tube with an outer surface of the tubular conductor engaging the inner rim of each open end to seal the open ends and defining a cooling chamber between the inner wall of the body and the tubular conductor. The heat sink is mounted inside the tubular conductor, and has multiple fins formed by continuously folding a metal sheet in a corrugated and annular form and abutting against an inner wall of the tubular conductor. The heat-dissipating apparatus increases the contact area between the heat sink and the tubular conductor and cooling channels, thereby providing a more satisfactory cooling effect.