Provided is a mask blank in which uniformity of the composition and optical characteristics of a phase-shift film in the in-plane direction and direction of film thickness is high, uniformity of the composition and optical characteristics of the phase-shift film between a plurality of substrates is also high, and defectivity is low even if a silicon-based material is applied to the material that forms the phase-shift film.A mask blank is provided in which a phase-shift film is provided on a transparent substrate, the phase-shift film having a function to transmit ArF exposure light therethrough at a predetermined transmittance and generate a predetermined amount of phase shift in the ArF exposure light that is transmitted therethrough, wherein the phase-shift film comprises a structure in which a low transmission layer and a high transmission layer are laminated, the low transmission layer and the high transmission layer are formed from a material consisting of silicon and nitrogen or a material consisting of silicon, nitrogen and one or more elements selected from semi-metallic elements, non-metallic elements and noble gases, and the low transmission layer has a relatively low nitrogen content in comparison with the high transmission layer.