A technique of inspecting an input print data file to determine whether or not a printed image has good reproducibility is provided. A content type identification module 321 identifies a content type of each object contained in the input print data file PD0. A characteristic value calculator 322 calculates a characteristic value relating to reproducibility of each object which is pre-selected according to the content type of the object. A characteristic value judgment module 323 determines based on the calculated characteristic value whether or not each object meets a judging condition relating to reproducibility of image portion represented by the object.