An electron gun (6) for use in a cathode-ray tube (10) that can reduce a spot dimension of an electron beam (7) when the electron beam (7) is in a high current range and that can suppress moire when the electron beam (7) is in a low current range, and a color cathode-ray tube (10) equipped with the foregoing electron gun (6), are provided. In the case where a current of the electron beam (7) is in a low current range, a maximum converging effect exerted on an outermost part in the vertical direction of the electron beam (7), in the vicinity of the third electrode (14) side of electron beam passage apertures (15), is weaker than a maximum converging effect exerted on an outermost part in the horizontal direction of the electron beam (7). In the case where a current of the electron beam (7) is in a high current range, in the electron beam passage apertures (17) of the second electrode (13) and in a space between the second electrode (13) and the third electrode (14), a maximum converging effect exerted on the outermost part in the horizontal direction of the electron beam (7) is substantially equal to a maximum converging effect exerted on the outermost part in the vertical direction of the electron beam (7).