PURPOSE: To obtain a cathode voltage stabilizing and controlling circuit having no probability causing the fluctuation in a cathode voltage even when the fluctuation in the cathode current of a CRT to be a subject occurs.

CONSTITUTION: This circuit is constituted so that the series circuit of first and second resistors 8, 9 are connected between the output terminal of a DC power source E and a reference potential point, and the output terminal of the DC power source E is connected to the corrector of an NPN transistor Q through a third resistor 6, and the emitter of the transistor Q is connected to the reference potential point, and a variable fourth resistor 5 is connected to the third resistor 6 in series, and the base of the transistor Q is connected to the connection central point of the first and second resistors 8, 9, and the cathode voltage applying to the cathode K of the CRT 1 is obtained from the corrector side of the transistor Q by constituting the third resistor 6 with a potentiometer.