An electrostatic painting method is disclosed in which air inside a paint feed channel is expelled when a color for painting is changed. An electrically conductive paint is channeled into a discharge channel of a fluid pathway, and the flow rate of the paint is measured. The fluid pathway is provided, via a paint valve, to a color changing valve mechanism, and communicates with a paint cartridge. The changing valve mechanism is provided in a distant position relative to a painting gun. Electrically conductive paint is channeled through a paint feed channel, which extends from the color changing valve mechanism to the painting gun, and air inside the paint feed channel is expelled. The paint feed channel is then filled with the electrically conductive paint according to the value measured for the flow rate.