Panel in a cathode ray tube having a flat outside and a curved inside surfaces, which can provide a perfect flat image at an appropriate distance of view, wherein a condition of 2.48×106(mm2)≦R×CFT≦4.38×106(mm2) is set for the CRT for use as a TV receiver, and a condition of 2.17×105(mm2)≦R×CFT≦6.93×105(mm2) is set for the CRT for use as a monitor, where R is a curvature represented by at least one of vertical, horizontal and diagonal curvatures of the inside surface of the panel and CFT is a center thickness of the panel.