A torque limiter (24) is interposed between a pressing roller (20) and a pressing roller shaft (21). When circumferential force greater than or equal to a set torque T is applied to the pressing roller (20), the torque limiter (24) allows the pressing roller (20) to rotate in the advance direction of paper sheet (P) relative to the pressing shaft (21) of the pressing roller (20), and when circumferential force applied to the pressing roller (20) is less than the set torque T, the torque limiter (24) causes the pressing roller (20) and the pressing roller shaft (21) to be in operative association with each other. The set torque T is less than friction force N3 and greater than both friction force N1 and friction force N4, the friction force N3 being friction force directly generated at a nip part (N), between a feed roller friction part (13) and a pressing roller friction part (23), the friction force N1 being friction force generated at the nip part (N), between the pressing roller friction part (23) of the pressing roller (20) and the paper sheets (P), and the friction force N4 being friction force generated at the nip part (N), between the pair of paper sheet (P). The pressing roller shaft (21) is adapted so as not to rotate in the advance direction of the paper sheets (P). ® KIPO & WIPO 2009