To provide a staple leg guiding mechanism, which can effectively guide the inside of the staple leg and the crown portion of the staple leg to be shot from a shooting passage, without causing a jam, etc.

A leg support 19 having a pair of supporting pieces 20 formed thereon to be arranged in the inside of the staple leg, and a crown support 24, which is arranged between the supporting pieces 20 and has a tilting surface 25 that is formed at its front end and is engageable with the crown portion of the staple, are provided below a pusher 15 for pushing the staple S formed as a U shape into a shooting passage so as to separately slide and so as to be forced to move forward. Tilting edges 21 are formed at the front end of the supporting pieces 20 of the leg support 19, and the tilting edges 21 are received within a slit port 23 formed in a face plate 13 across the shooting passage.