A photomask blank comprising a transparent substrate and a chromium-containing film deposited thereon is provided. The chromium-containing film comprises at least one CrC compound layer comprising up to 50 at% of Cr, at least 25 at% of O and/or N, and at least 5 at% of C. From the blank, a photomask having a photomask pattern formed on the substrate is produced, the photomask being used in photolithography of forming a resist pattern with a line width of up to 0.1 µm, using exposure light having a wavelength of up to 250 nm.