PURPOSE: To provide an aging method for a field emission cold cathode in which is the emission of electrons from the cathode by opening the gate of the field emission cold cathode stabilized.

CONSTITUTION: A field emission cold cathode 10, in which a plurality of cavities are made on a substrate 10 and a conical cathode 14 is arranged within the cavity, and which possesses a gate on the insulating layer forming the cavity, is accommodated in the valve 2 of a cathode-ray tube 1. This is an aging method for a field emission cold cathode 10 which stabilizes the electron emission from the gate 14 of the field emission cold cathode 10 by applying high voltage to the anode 3 or the converging electrode 4 of the electron gun of the cathode-ray tube 1 thereby floating the gate 17.