PURPOSE: To improve withstand voltage characteristics and prevent the clogging of a shadow mask by removing the magnetic metallic fine powder generated when attaching and detaching are repeated between a panel pin and a mask spring, before execution of the sealing process between a panel and a funnel.

CONSTITUTION: A panel structure body is retained by covering the external surface side of a panel 1 with a vacuum sucking disk 11. This sucking disk is rigidity-connected to an exciter 12 and applies vibration to the panel. In addition, an AC magnetic eraser 13 is mounted on the outer frame 14 of a color cathode- ray tube at the position corresponding to the outside of the panel pin. When 15Hz vibration is applied to the panel structure body and at the same time magnetic erasing is peformed for approximately 10 seconds by the AC magnetic eraser 13, the dirt that is made to adhere to magnetically is let to fall. When a cathode-ray tube is manufactured by coupling a funnel, after this process, a product with high reliability that hardly contains something foreign in the tube can be obtained.