PURPOSE: To reduce a pattern distortion irrespective of both a center axis slip and an electron lens distortion produced in time of sealing an electron gun and a vacuum envelope, by installing a positive pole electrode between a positive electrode and a shield mesh electrode independent of the positive electrode that is stuck and made up on the inner wall of a funnel.

CONSTITUTION: An electron gun to be installed inside a neck 13 consists of an electron beam generating electrode group 20, a paired vertical deflecting plate 22, a paired horizontal deflecting plate 23, a collector electrode 24 for secondary electron absorption and pattern distortion correction use, a shield mesh supporting electrode 25, a shield mesh electrode 26 and a shield electrode 24 between deflecting plates. A positive pole electrode 40 is impressed with the specified high voltage out of an anode 34 via a conductive contact arm 41. The region of an electron lens 37 conductive toward the extension of deflection is almost determined with a distance for a diameter of the shield mesh 26 or thereabouts whereby this distance is negligible at the region of the anode 34 so that such a tube structure that these problems such as an error of sealing accuracy in the electron gun, positioning accuracy in a valve spacer 29, out of roundness in a funnel 12, inclination in the neck 13, etc., will not concern distortion in an electron lens 37 can be brought to fruition.