A photomask blank (1) having: a transparent substrate (10); a first film (11) etched by chlorine/oxygen-based dry etching and made of a material having resistance against fluorine-based dry etching; and a second film (12) formed adjacent to the first film and made of a material which comprises silicon and oxygen or silicon, oxygen, and nitrogen and has an Si—Si bond and which is substantially not etched by chlorine/oxygen-based dry etching, wherein: the photoresist adhesive performance is improved; the resist pattern is stably maintained without degrading, collapsing, or peeling even when a fine resist pattern is formed from a photoresist film; and an excellent shape and dimensional accuracy is obtained in regard to etching of a lower layer film in which the resist pattern is used.