A main lens section of an electron gun assembly includes a focus electrode supplied with a focus voltage of a first level, a dynamic focus electrode supplied with a dynamic focus voltage obtained by superimposing an AC component, which varies in synchronism with deflection magnetic fields, upon a reference voltage close to the first level, and an anode supplied with an anode voltage with a second level higher than the first level. The electron gun assembly further includes at least two auxiliary electrodes disposed between the focus electrode and the dynamic focus electrode, and these at least two auxiliary electrodes are connected via a resistor disposed near the electron gun assembly.