A method of making a graphite film is provided. The method is characterized in that a polyimide film is used as a precursor, and a carbonizing heat treatment is performed, in which the carbonizing temperature ranges from 500 to 800 degrees Celsius and the heating rate is equal to or lower than 2 degrees Celsius per minute. The highest carbonizing temperature is equal to or higher than 1000 degrees Celsius. The method is also characterized in that the graphitizing temperature ranges from 2200 degrees temperature to the highest graphitizing temperature in which the average heating rate is equal to or lower than 3 degrees Celsius per minute. The highest graphitizing temperature is equal to or higher than 2500 degrees Celsius.