1. An image file sorting method executed by an image file sorting device, including a storage unit, a control unit, and an image reading unit, wherein the storage unit includes a sorting condition storage unit that stores a sorting condition to specify a sorting destination of an image file, the method comprising a sorting keyword extracting step of extracting a sorting keyword from a marker portion of the image file read by the image reading unit; a sorting destination deciding step of deciding the sorting destination of the image file by collating the sorting keyword extracted by the sorting keyword extracting step and the sorting condition stored in the storing condition storage unit; and an image file sorting step of sorting the image file into the sorting destination decided by the sorting destination deciding step.