A method for manufacturing a positive active material for a nonaqueous electrolyte secondary battery having both thermal stability and charge-discharge capacity at a high level as well as excellent cycle characteristics. The method for manufacturing a positive active material for a nonaqueous electrolyte secondary battery includes: a step of adding a niobium salt solution and an acid simultaneously to a slurry of a nickel-containing hydroxide, and controlling the pH of the slurry at between 7 and 11 on a 25° C. basis to obtain a nickel-containing hydroxide coated with a niobium compound; a step of mixing the nickel-containing hydroxide coated with the niobium compound with a lithium compound to obtain a lithium mixture; and a step of firing the lithium mixture in an oxidizing atmosphere at 700° C. to 830° C. to obtain a lithium-transition metal composite oxide.