To provide an image forming device capable of allowing a user to easily set tray information, and executing consistent image forming actions even when a paper feed tray has no automatic paper sheet detection function.

The image forming device 100 comprises a paper feed tray 3 for accommodating paper sheets, and a body 1 having an image forming unit 18 for forming an image to a paper sheet fed from the paper feed tray 3 based on the tray information 30. The paper feed tray 3 has a first holding means 4 for holding the tray information 40 corresponding to the tray. The body 1 comprises a second holding means 13 for holding the tray information 30 used in the image forming unit 18, a reading means 19 for reading the tray information 40 from the first holding means 4 when the paper feed tray 3 is attached, and a first setting means 52 for setting the tray information 30 held by the second holding means 13 based on the read tray information 40.