To provide a binding device having excellent bookbinding finishing precision.

This binding device equipped with an electric stapler and a paper folding mechanism is provided with a mechanism for sliding the electric stapler 3 in parallel with respect to a paper table 2, and a clamp roller 8 for clamping paper near a binding position. In a waiting condition, a driver of the electric stapler and an operation central line of a paper folding mechanism coincide with each other, and the electric stapler moves backward and retreats from an operation passage of the paper folding mechanism after stapling the paper P on the paper table. Next, a push blade 9 of the paper folding mechanism is raised, and the binding portion of the paper is inserted between pinch rollers 6, and the paper is pressed in the double folded state by the rotating pinch rollers. Since the paper P is pressed by the clamp roller 8 at stapling and at paper folding, dislocation of the paper does not occurs. Therefore, excellent finish precision can be achieved.