A sheet post-processing apparatus includes a first regulating device regulating a position of a sheet bundle, by contacting to an end part of the sheet bundle conveyed in a conveying direction by a conveying device and stacked on a stacking device in a direction intersecting with the conveying direction; a second regulating device regulating a position of the sheet bundle in the conveying direction, by contacting to an end part of the sheet bundle stacked on the stacking device in the conveying direction; a first binding device configured to move from one side to another side of the sheet post-processing apparatus and from the other side to the one side by moving in the intersecting direction, and configured to bind a corner part of the sheet bundle using a staple, and a second binding device configured to bind a corner part of the sheet bundle without a staple.