To provide a binding machine hanging a binding tape around an object to be bound followed by pulling back, and removing the looseness to bind.

This binding machine is such that a tension arm 21 which reacts on closing action of a clincher arm 2, and a block lever 22 which regulates rotation of the tension arm 21 are rotatably set on a spindle 20 of a binder body, an engagement part 27 which is engageable with an edge engagement axis 37 of an actuating arm 23 connected to the clincher arm 2 is formed on the tension arm 21, and a block part which inhibits the engagement axis 37 of the actuating arm 23 from engaging with the engagement part 27 is formed on the block lever 22. The engagement axis 37 of the tension arm 21 is engaged with the engagement part 27 by rotating the block lever 22 by tension of a binding tape T pulled out when hanging around an object to be bound and letting the block part escape and move to the outside of the engagement part 27, and the binding tape T is pulled back by rotating the tension arm 21 with the actuating arm 23 when the clincher arm 2 makes a closing action.