To minimize the curl of a sheet in reverse discharge of the sheet and smoothen the discharge by setting the mutual angles formed by the lines connecting the combining points of a plurality of guide passages to the nip parts of discharge passage carrying roller pairs to specified values, respectively.

The straight line connecting the branch point 120a between a direct discharge passage 12 and a reverse passage 121 to the nip part of an upstream discharge roller pair 105 is taken as L1. The straight line connecting the branch point 120b between the reverse passage 121 and a reverse discharge passage 122 to the nip part of a reverse feed roller pair 106 is taken as L2. The straight line L3 connecting the combining point 120c between the direct discharge passage 12 and the reverse discharge passage 122 to the nip part of a downstream discharge roller pair 107 is taken as L3. The mutual angles formed by these lines are set to substantially equal angles of 120±100. Therefore, the curl of a sheet P moving in the reverse passage 121 is minimized, and it can be smoothly and quickly guided and carried even when it is reversely curved and carried in the reverse discharge passage 122.