To provide a sheet discharge device 125 capable of improving convenience of users by changing a discharge method of sheets according to the degree of trouble of a sensor for detecting discharge of a sheet.

A sheet discharge device 125 includes: sensor monitoring means 403 for determining whether or not output time of an ON signal of a discharge full sensor is abnormal; count determination means 404 for, when the output time is abnormal, counting the number of sheets discharged after a start key is pressed, and determining whether or not the counted number of sheets reaches a predetermined number; signal determination means 405 for, when the counted number of sheets reaches the predetermined number, determining whether or not the ON signal is still outputted; and discharge control means 406 for, when the ON signal is still outputted, locating a sheet having been discharged last at a position where the discharge full sensor outputs the ON signal, and when the sheet having been discharged last is removed, making the counted number of sheets be reset.