An electric stapler includes: a driver for driving leg portions of a staple having a U-shaped section to penetrate the leg portions through a paper bundle; a table including a clincher for bending and forming the penetrated leg portions inwardly, the table for holding the paper bundle between the driver and the table; a motor for moving the table and the driver; a photo sensor for detecting an existence of the paper bundle inserted into a gap between the table and the driver; and a control portion for driving the motor. The photo sensor is disposed on the table in such a manner that a detection point of the photo sensor for detecting the paper bundle exists upwardly of a disposing position of the clincher by inclining an optical axis direction of a radiation light to be emitted from the photo sensor in a direction of the clincher.