A photomask blank comprising a transparent substrate and a chromium-containing film is provided. The chromium-containing film is constructed by one or more chromium compound layers which are formed of a chromium compound containing Cr, N and optionally O, and have a composition having a Cr content ≧30 at % and a total Cr+N+O content ≧93 at %, and meeting the formula: 3Cr≦2O+3N. A chromium compound layer meeting a first composition having an N/Cr atomic ratio ≧0.95, a Cr content ≧40 at %, a total Cr+N content ≧80 at %, and an O content ≦10 at % is included to a thickness of more than 70% to 100% of the overall thickness of the chromium-containing film.