A method of manufacturing a reflective mask blank includes: forming a multilayer reflective film, which is configured to reflect EUV light, on a substrate to form a substrate with a multilayer reflective film; subjecting the substrate with a multilayer reflective film to defect inspection; forming an absorber film, which is configured to absorb the EUV light, on the multilayer reflective film of the substrate with a multilayer reflective film; forming a reflective mask blank, in which an alignment region is formed in an outer peripheral edge region of a pattern formation region by removing the absorber film so that the multilayer reflective film of an area including an element serving as a reference of defect information on the multilayer reflective film is exposed in the alignment region; and performing defect management of the reflective mask blank through use of the alignment region.