An image processing device inputs shading correction data, which can identify the image processing device itself, to a first hash function and generates comparison data. The image processing device inputs the shading correction data to a second hash function, and generates tracing identification data. The image processing device generates a tracing pattern from the tracing identification data, and adds the tracing pattern to output image data. The image processing device verifies the comparison data with standard data, which has been generated by inputting the shading correction data in a first function and previously stored in a storage device. When the comparison data matches the standard data, the image processing device permits to print out the output image data to which the tracing pattern has been added.