A cathode-ray tube that has an electron gun comprising a last-stage main lens made up of a last accelerating electrode (6) and the focusing electrode (5) and having a focus function stronger in horizontal direction than in vertical direction, an electron lens of the first kind formed inside the focus electrode (5) and having a focus function stronger in vertical direction than in horizontal direction to vary the cross sectional shape of an electron beam with an increase of the deflection amount, an electron lens of the second kind formed inside the focus electrode (5) for weakening the lens strength with an increase of the deflection amount of an electron beam, and an electron lens of the third kind made up of at least one electrode constituting a three electrode section and having a focus function stronger in horizontal direction than in vertical direction. The dynamic focus voltage which decreases with an increasing deflection amount is reduced. The horizontal diameter of an electron beam spot is reduced on the central area of the screen.
