To provide a paper sheet separation mechanism and an automatic ticket checking and collecting device capable of preventing the deterioration of separation performance and reducing defective separation.

An automatic ticket checking and collecting device in which a plurality of tickets can be input in a lump laid one on top of another has a separation section 12 which separates the tickets input in a lump and sends them one by one. The separation section 12 has a feed roller 91 and a separation roller 92 holding a main conveyance passage 11 between them in a vertical direction. To prevent the deterioration of the separation of tickets in the separation section 12, with a ticket not conveyed through the main conveyance passage 11, the feed roller 91 and the separation roller 92 are rotated at speeds different from each other and are slidden on each other, and the outer peripheral face of the separation roller 92 is cleansed.