A booklet processing apparatus includes a pressing member and a rotating unit. The pressing member presses a folded portion of a booklet formed to extend in one direction and having the folded portion on the downstream side in the one direction. The pressing member is provided so as to be rotatable about a rotary shaft that extends along the folded portion. The rotating unit rotates the pressing member so as to move a portion of the pressing member that confronts the folded portion downstream in the one direction so that the portion of the pressing member that confronts the folded portion is changed to a different portion.

A sheet discharging device includes a shift tray 202 on which a sheet P1 is stacked, a discharging roller 6 that discharges a sheet P2 onto the shift tray 202, a blowing device 230 that sends air to a lower surface of the sheet P2 discharged by the discharging roller 6, a blocking member 231 that blocks air sent to the lower surface of the sheet P2 from a blowing port 230-2 of the blowing device 230, and a control unit that controls the blocking amount of the blocking member 231. The blocking amount is determined based upon sheet information including sheet-type information, sheet-size information, and sheet-thickness information, for example.