PURPOSE: To provide an image pickup tube which has no characteristic variations and has a high reliability by supporting an electron gun so that any axial shift of the electron gun in an outer case doesn't develop even when there caused a thermal expansion of the electron gun.

CONSTITUTION: The end of a rod 1, which is fixed to a stem 7, is fixed to a lower part 2a of a G3 electrode 2 by welding. Therefore, when the temperatures of a G1 electrode 5 and a G2 electrode 6 increase due to temperature rise of a cathode 4 caused by heating the cathode 4 by feeding a current to a heater 3, the electrodes 5 and 6 undergo thermal expansion and expand toward a stem 7. Here, the electrical connection between the electrodes 5 and 6 is achieved by use of a ribbon member in order to absorb the expansions of the electrodes 5 and 6. Owing to the above constitution, the degree of the shift toward a target 8 of the whole electron gun becomes extremely small. Besides, the temperature rise of a part, which extends from the lower part 2a of the G3 electrode 2 to the target 8, can be made below 1/10 the temperature rise of a part around the G1 electrode 5.