PURPOSE: To easily and precisely align the center axis without requiring a high- degree skill, by heating the neck portion of an air-exhausted CRT with the surrounding space thereof is evacuated and carrying out fine adjustment while observing an image produced by an electron beam.
CONSTITUTION: The main portion of the aligning means is constructed from an aligning mechanism for affixing a glass tube 1 and heating and softening in vacuum the neck portion of the tube to adjust the center axis, a heating temperature controller, and a vacuum controlling power unit including a power supply for vacuum control and electron beam projection. When a start button is depressed after affixing the CRT 1, a heater 30 and a vacuum pump 35 are operated in a predetermined manner and the center axes of the glass tube 1 and the electron gun 2 can be alighed by operating an adjusting handle 17 etc. to measure the displacement between the center axis and the projected image and further operating a handle 37 etc. while observing the image projected by the electron beam during the center axis aligning operation. In this manner, one cycle with be completed by the control according to the settings of the temperature controller and the vacuum controlling power unit.