An electron gun for a color cathode ray tube includes cathodes, a control electrode and a screen electrode which form a front triode, first, second, third, fourth and fifth focus electrodes which form a plurality of auxiliary electrostatic lenses, and a final accelerating electrode installed adjacent to the fifth focus electrode to form a main electrostatic lens, wherein vertically-elongated electron beam passing holes are formed on the fourth focus electrode, a predetermined focus voltage is applied to the first, second and fifth focus electrodes, a dynamic focus voltage lower than the focus voltage and synchronized with a deflection synchronizing signal is applied to the fourth focus electrode, a static voltage higher than the focus voltage is applied to the second focus electrode, and an anode voltage higher than the focus voltage is applied to the final accelerating electrode.