The image forming device capable of executing an authentication print printing includes: a communication interface for receiving job data; a job data property deriving unit for deriving a property of the job by referencing data contained in the job data other than data explicitly indicating to execute/not to execute the authentication print printing and outputting the property as job property data; an authentication print setting deciding unit for deciding whether or not to execute the job as the authentication print printing; an authentication unit; a user authentication unit for outputting the result of the user authentication; and a job executing unit for executing the job related to the job data.