A mask blank including a phase shift film is provided, wherein the phase shift film has a predetermined transmittance and a predetermined phase difference with respect to exposure light of an ArF excimer laser, and it is relatively easy to detect an etching end point for detecting a boundary between the phase shift film and a transparent substrate upon the EB defect repair.The phase shift film has a function to transmit the exposure light of the ArF excimer laser at a transmittance of not less than 10% and not more than 20%, and a function to generate a phase difference of not less than 150 degrees and not more than 190 degrees between the exposure light transmitted through the phase shift film and the exposure light transmitted through the air for the same distance as a thickness of the phase shift film. The phase shift film is made of a material containing a metal, silicon, nitrogen, and oxygen. A ratio of the metal content to the total content of the metal and silicon in the phase shift film is not less than 5% and not more than 10%, the oxygen content in the phase shift film is 10 atom % or more, and the silicon content in the phase shift film is three times or more the oxygen content.