PURPOSE: To ensure simple and accurate alignment adjustment of a TV camera, by superposing a low-frequency signal on the focusing voltage or a focusing magnetic field.

CONSTITUTION: When a low-frequency signal of 0.1∼5Hz is applied to the focusing voltage, the modulation degree drops together with reduction of a distance from the center of a screen. An optimum alignment state is obtained by adjusting the alignment so that the modulation degree drops radially from the center of the screen. For the alignment adjustement, it is required that the level of a color signal which is considered basically as a modulation degree signal is constant within a screen and at the same time the focused voltage has a change proportional to the distance from the center of the screen. Then the alignment is adjusted so that both red and blue separate waveforms repeat simultaneously a parabola and an adverse parabola in case the focusing voltage is changed by means of the red and blue separate waveforms.