PURPOSE: To improve voltage resistance characteristic through effective soft flash function by providing a second anode electrode for seasoning at a part of resistance body formed at the funnel part.

CONSTITUTION: A second anode electrode 10 is provided to an internally coated film 8c which is a part of a resistance body in addition to a first anode electrode 7 connected to the internally coated film 8a. In the seasoning processing, an anode voltage is applied to the second anode electrode 10 and a high voltage is applied to an electron gun 6 through the internally coated film 8c. Namely, the seasoning is carried out, without the internally coated film 8b having a high resistance value. Meanwhile, since a high voltage is applied to the first anode electrode 7 during operations, the soft flash function of the internally coated film 8b can be obtained effectively.