Abstract: A heat dissipating apparatus of a computer system is used for a first heat generating component (such as an interface card and a display card) of the computer system without being interfered by a second heat generating component (such as a hard disk drive and an optical disk drive) of the heat dissipating apparatus. The heat dissipating apparatus has a rack installed between the first and second heat generating components, corresponding openings on both sides of the rack, a fan between the openings, and holes disposed on the casing and corresponding to the openings of the rack. The fan is rotated to drive external cold air into the casing through the openings of the rack from the holes of the casing and blown at the first heat generating component directly to improve the heat dissipating effect without being interfered by the second heat generating component in the casing.