In a photomask blank serving as a base member for producing a halftone-type phase shift mask in which a light-transmissive substrate is formed thereon with a light-semitransmissive phase shift pattern having a desired opening, a light-semitransmissive phase shift film, a chromium film, and an etching mask film are stacked in order on the light-transmissive substrate. The etching mask film is made of an inorganic-based material having a resistance against dry etching of the chromium film. The photomask blank further may has a resist film formed on the etching mask film.