There is provided a shadow mask for a cathode ray tube, including a plate having a first surface and a second surface. The plate is formed with at least one line of slots between which bridge portions are formed, each slot being spaced away from adjacent slots by a predetermined pitch P. The bridge portions are defined by a first length at the first surface of the plate and a second length at the second surface of the plate, the first and second lengths being determined so that a factor R is in the range of 5% to 15%, wherein the factor R is defined as a ratio of the smaller of the first and second lengths, to the predetermined pitch P. By setting the factor R in the range of 5% to 15%, it is possible to enhance the mechanical strength of the shadow mask without deterioration of brightness characteristic of the shadow mask.