Abstract: A perforated curved-surface portion of a shadow mask in a color picture tube satisfies the following conditions. At an arbitrary point on an X-axis and a Y-axis, Rr is one radius of curvature of a main radius of curvature group, and R1 is the other radius of curvature of the main radius of curvature group. On the Y-axis, |Rr|<|R1| is satisfied at an arbitrary point in a range where the distance from a center is LY or less. On the X-axis, |Rr|>|R1| is satisfied at an arbitrary point in a range where the distance from the center is Lx/3 or less, and |Rr|<|R1| is satisfied at an arbitrary point in a range where the distance from the center is 3 Lx/4 to LX. This can enhance mask curved-surface strength without degrading resolution and color purity.