The radius of curvature of the outer surface of a panel (3) is 10,000 mm or more, and a shadow mask (7) is made of a material containing 95% or more of iron. A sagging amount change curve along a curve C1 on the surface of the shadow mask (7), which a plane passing through a center P0 of a useful area of the shadow mask (7) and parallel to a tube axis and a major axis crosses, satisfies a particular Condition 1. Assuming that an intersection between the curve C 1 and a useful area end of the shadow mask (7) is a major axis end PL, a distance from the center P0 to the major axis end PL along a major axis is W, and a point on the curve C1 away from the center P0 by 2/3 × W in the major axis direction is P1, a sagging amount change curve along a curve C2 on the surface of the shadow mask (7), which a plane passing through the point P1 and parallel to the tube axis and the minor axis crosses, satisfies a particular Condition 2. Consequently, a color picture tube can be realized, which has satisfactory visibility, and less degradation in color purity caused by doming while having a shadow mask made of an inexpensive material with satisfactory moldability.