A paper-sheet recognition apparatus includes a base plate; and one or a plurality of line sensors engaged in the base plate. An engaging portion between the line sensor and the base plate has a concave-convex engaging structure in which a concave-convex portion provided in the line sensor and a concave-convex portion provided in the base plate are engaged with each other, a convex portion of the concave-convex portion provided in the line sensor has the same size as a convex portion of the concave-convex portion provided in the base plate in the direction perpendicular to the paper-sheet transport direction, each of the concave-convex portions is formed having an inclined surface that extends downwardly from a horizontal plane, and edges of end faces of the concave-convex portions and boundaries between a horizontal plane of the base plate and the inclined surfaces of the concave-convex portions are round chamfered.