A binding apparatus comprising: a binding mechanism for binding a plurality of sheets, in particular paper sheets between a stitcher section and a clincher section with a staple needle, said binding mechanism being equipped with said stitcher section including a staple needle storing section and a needle pushing out section and with the clincher section for bending one end of said needle in a separate manner; a pair of guide shafts (200a, 200b) for guiding said stitcher section and said clincher section to support said binding mechanism in a parallel manner; a front side plate, a rear side plate and a pair of guide plates (204, 205), wherein the pair of guide shafts (200a, 200b) and the pair of guide plates (204, 205) are fixed to the front side plate and the rear side plate and serve as stays; moving mechanisms (206, 207, 208, 209, 210, 211, 212) for moving said binding mechanism along said guide shafts (200a, 200b); wherein a position controlling member (202a, 203a) for limiting the position of said guide shafts (200a, 200b) and another controlling member for limiting the position of said binding mechanism around each of said guide shafts (200a, 200b) as a center thereof are pair-wise disposed, and a channel for moving a binding needle pushed out from said stitcher section is disposed in the vicinity of a center line connecting the centers of said guide shafts (200a, 200b), viewed in the axial direction of said guide shafts (200a, 200b), wherein said moving mechanism comprises a timing belt (208, 209) disposed parallel to said guide shafts (200a, 200b), a driving mechanism (206, 207, 210, 211) for driving said timing belt (208, 209) and a motor for supplying a driving force to said driving mechanism (206, 207, 210, 211), characterized in that the guide plates (204, 205) in the stays are each machined from a thin metal sheet having a thickness of 0.8 to 1.2mm such that its basis form has a U-shaped cross-section, viewed in a direction perpendicular to the longitudinal direction of the front and the rear side plates (214, 215), wherein inner spaces (A, B) of the U-shaped guide plates (204, 205) are used for channels in which a harnesse connected to the binding mechanism are installed. a binding mechanism for binding a plurality of sheets, in particular paper sheets between a stitcher section and a clincher section with a staple needle, said binding mechanism being equipped with said stitcher section including a staple needle storing section and a needle pushing out section and with the clincher section for bending one end of said needle in a separate manner; a pair of guide shafts (200a, 200b) for guiding said stitcher section and said clincher section to support said binding mechanism in a parallel manner; a front side plate, a rear side plate and a pair of guide plates (204, 205), wherein the pair of guide shafts (200a, 200b) and the pair of guide plates (204, 205) are fixed to the front side plate and the rear side plate and serve as stays; moving mechanisms (206, 207, 208, 209, 210, 211, 212) for moving said binding mechanism along said guide shafts (200a, 200b); wherein a position controlling member (202a, 203a) for limiting the position of said guide shafts (200a, 200b) and another controlling member for limiting the position of said binding mechanism around each of said guide shafts (200a, 200b) as a center thereof are pair-wise disposed, and a channel for moving a binding needle pushed out from said stitcher section is disposed in the vicinity of a center line connecting the centers of said guide shafts (200a, 200b), viewed in the axial direction of said guide shafts (200a, 200b), wherein said moving mechanism comprises a timing belt (208, 209) disposed parallel to said guide shafts (200a, 200b), a driving mechanism (206, 207, 210, 211) for driving said timing belt (208, 209) and a motor for supplying a driving force to said driving mechanism (206, 207, 210, 211), characterized in that the guide plates (204, 205) in the stays are each machined from a thin metal sheet having a thickness of 0.8 to 1.2mm such that its basis form has a U-shaped cross-section, viewed in a direction perpendicular to the longitudinal direction of the front and the rear side plates (214, 215), wherein inner spaces (A, B) of the U-shaped guide plates (204, 205) are used for channels in which a harnesse connected to the binding mechanism are installed.