PURPOSE: To provide a paper at a sheet conveyer for enabling paper sheets to make obverse/reverse conversion or direction change high speed.

CONSTITUTION: A paper sheet conveyer is provided with a carrying-in means 2 for carrying in paper sheets 1a in an arrow A direction, a carrying-out means 3 for carrying out paper sheets 1a in an arrow C direction, and the first guide means 4 positioned between the carrying-in means 2 and the carrying-out means 3, and guiding the rear end of the paper sheets 1a from the carrying-in means 2 to the carrying-out means 3 by introducing the tip end of the paper sheets 1a upward.