PURPOSE: To provide an inexpensive correcting lens by which a phosphor film for providing a high-resolution cathode-ray tube can be formed at high accuracy, a forming metal mold suitable for forming the correcting lens, a method and a device for manufacturing the forming metal mold, and a method for forming the correcting lens.

CONSTITUTION: In a correcting lens used for forming a pattern on the phosphor screen of a cathode-ray tube and comprising a plurality of planes of different inclinations relative to a reference plane 2c, or a plurality of curved surfaces 2b, the lowest point of the plurality of planes or curved surfaces 2b is situated where the difference in height at the boundary between adjacent planes is at its minimum, and one side of each of the plural planes or curved surfaces 2b is reduced to 2mm or less, whereby the difference 2a in height at the boundary between adjacent planes is reduced.