An Fe-Ni alloy sheet for a shadow mask, which consists essentially of:nickel: from 34 to 38 wt. %,silicon: from 0.01 to 0.15 wt. %,manganese: from 0.01 to 1.00 wt. %, andthe balance being iron and incidental impurities;the surface portion of the alloy sheet having a silicon (si) segregation rate, as expressed by the following formula, of up to 10%: ##EQU1## and the alloy sheet having a surface roughness which satisfies all the following formulae (1) to (3):0.3 .mu.m.ltoreq.Ra.ltoreq.0.8 .mu.m (1)where, Ra: center-line mean roughness;3.ltoreq.Rkr.ltoreq.7 (2)where, Rkr: kurtosis which is a sharpness index in the height direction of the roughness curve; and ##EQU2## The above-mentioned alloy sheet is manufactured by: preparing an alloy sheet, which has the above-mentioned chemical composition, and imparting a surface roughness which satisfies all the above-mentioned formulae (1) to (3) to the both surfaces of the alloy sheet by means of a pair of dull rolls during the final rolling of the alloy sheet for that preparation. The thus manufactured alloy sheet is excellent in etching pierceability and free from seizure of the flat mask during the annealing thereof.