A stapler includes a main body, a magazine having a pair of sidewalls and a tip end wall, a driver, a clincher, and a cover. The magazine is configured to be movable between a first position and a second position. A staple is capable of being taken in and out from an opening formed above the pair of sidewalls and the tip end wall when the magazine is located at the second position. The cover is attached to the main body so as to be displaceable between a third position and a fourth position. When the cover is located at the third position and the magazine is located at the second position, the cover covers the pair of sidewalls, the tip end wall and the opening of the magazine in a state of protruding from the main body.