Laminated molded object production method and production device

A method for manufacturing an additively-manufactured object in which deposition is performed by melting and solidifying a metal depending on three-dimensional shape data of a target shape, the method comprising:

• acquiring the three-dimensional shape data;
• creating a deposition plan in which a formation track in which each layer obtained by slicing a shape of the three-dimensional shape data is formed by the metal and a heating condition of the metal are determined;
• determining a difference between a shape of the additively-manufactured object that thermally contracts by cooling after deposition and a shape of the three-dimensional shape data by an operation in a case where the additively-manufactured object is built by the deposition plan;
• modifying the deposition plan by changing the formation track and the heating condition until the difference falls within a predetermined allowable range;
• and
• additively manufacturing the additively-manufactured object based on the deposition plan in which the difference falls within the allowable range.