An in-line type triple electron gun assembly wherein there is provided a central electron gun member; there are disposed on both sides of the central electron gun member in the same plane a pair of electron gun members whose axis defines a prescribed angle of inclination to that of the central electron gun member; the first and second grid electrodes of each of the paired electron gun members consist of a substantially triangular plate electrode; the plate electrodes of each of the three electron gun members have an effective surface intersecting the axis of said each member at right angles; and each plate electrode is perforated with an electron beam hole coaxial with the axis of the electron gun member.