A recording medium post-processing apparatus includes a recording medium stacking member; a first binding member that moves to an inside of a stacked area, binds the recording media by deforming the recording media, and moves to an outside of the stacked area after binding the recording media; and a guiding member disposed between the first binding member and the recording media and fixed to the first binding member, the guiding member guiding the recording media so that a gap between the recording media and the first binding member is maintained when the first binding member moves around the inside of the stacked area, wherein the guiding member has an opening that surrounds an area in which the first binding member operates to deform the recording media, and a part of the opening is narrowed in a moving direction of the first binding member.