A sheet processing apparatus for processing a sheet in the course of conveyance of the sheet, wherein: the sheet processing apparatus comprises a plurality of slitters aligned in a width direction, wherein each of the plurality of slitters comprises: an upper rotary blade; a lower rotary blade; an upper housing for holding the upper rotary blade; and a lower housing for holding the lower rotary blade, the slitter being constructed such that the rotary blades (71, 72) revolve in a manner such that a tip on a cutting surface side of the upper rotary blade and a tip on a cutting surface side of the lower rotary blade are rubbed together so that a sheet passing through between the rotary blades (71, 72) is cut, wherein one rotary blade (71 or 72) selected from the upper rotary blade and the lower rotary blade is cantilevered on the cutting surface (711 or 721) side of the one rotary blade (71 or 72) by a first cantilevered supporting part (78 or 79); and all of the plurality of slitters are provided such as to cut the sheet along a direction of conveyance of the sheet; characterized in that: for each of the plurality of slitters, the other rotary blade (72 or 71) selected from the upper rotary blade and the lower rotary blade is held by an at-both-ends supporting part, and the at-both-ends supporting part includes an inclination adjustment part for adjusting an inclination of a shaft center of a second revolving shaft (742 or 741) for supporting the other rotary blade (72 or 71). the sheet processing apparatus comprises a plurality of slitters aligned in a width direction, wherein each of the plurality of slitters comprises: an upper rotary blade; a lower rotary blade; an upper housing for holding the upper rotary blade; and a lower housing for holding the lower rotary blade, the slitter being constructed such that the rotary blades (71, 72) revolve in a manner such that a tip on a cutting surface side of the upper rotary blade and a tip on a cutting surface side of the lower rotary blade are rubbed together so that a sheet passing through between the rotary blades (71, 72) is cut, wherein one rotary blade (71 or 72) selected from the upper rotary blade and the lower rotary blade is cantilevered on the cutting surface (711 or 721) side of the one rotary blade (71 or 72) by a first cantilevered supporting part (78 or 79); and all of the plurality of slitters are provided such as to cut the sheet along a direction of conveyance of the sheet; characterized in that: for each of the plurality of slitters, the other rotary blade (72 or 71) selected from the upper rotary blade and the lower rotary blade is held by an at-both-ends supporting part, and the at-both-ends supporting part includes an inclination adjustment part for adjusting an inclination of a shaft center of a second revolving shaft (742 or 741) for supporting the other rotary blade (72 or 71). for each of the plurality of slitters, the other rotary blade (72 or 71) selected from the upper rotary blade and the lower rotary blade is held by an at-both-ends supporting part, and the at-both-ends supporting part includes an inclination adjustment part for adjusting an inclination of a shaft center of a second revolving shaft (742 or 741) for supporting the other rotary blade (72 or 71).