An image processing device inserts an AR (Augmented Reality) marker in documents. The AR marker is to deliver an air tag which corresponds to the AR marker from an air tag server to a terminal device, when the terminal device which reads the AR marker satisfies deliver conditions. The image processing device identifies the air tag which is to be delivered from among air tags stored in the air tag server. The image processing device acquires the AR marker which corresponds to the air tag which is to be delivered from the air tag server. The image processing device inserts the acquired AR marker into the document.