In a cathode ray tube which has a cathode and first and second electrodes provided with electron penetration holes and of which the first and second electrodes are coaxially disposed in front of the cathode so that an electron beam extracted from the cathode may pass through their respective electron penetration holes, an increase in luminance of the cathode ray tube is realized by adjusting the cathode voltage in cutoff at 50V to 80V with the reference of the first electrode.
