Abstract: Two slide bases (106) synchronizingly traveled on linear guides (105) arranged upwardly and downwardly in parallel with each other are rotatably attached with a clincher unit (107) and a driver unit (104) and provided with a click stop mechanism for fixing the clincher unit (103) and the driver unit (104) at a 0 degree position or a 45 degree rotated position. Respective outer peripheral portion thereof are provided with claw portions (119), (120), in correspondence with the 0 degree position and the 45 degree rotated position and a stopper pin (121) is arranged at a traveling path. When the driver unit and the clincher unit are traveled from an initial position to a skewed binding position, the 0 degree claw portion 119 impinges on the stopper pin (121) and the driver unit and the clincher unit are rotated to the 45 degree rotated position to fix.