A sheet-type medium separating apparatus applicable in a self-service financial device for reliable sheet-by-sheet separation of an entire stack of banknotes. The apparatus includes a pickup roller component; a reversal roller component; and a separation roller component, where the reversal roller component includes a reversal roller, the reversal roller is fitted onto a reversal roller shaft via a one-way bearing, the reversal roller is provided with an inner sleeve cylinder fixed with the one-way bearing and a reversal roller sleeve sleeved onto the inner sleeve cylinder and capable of moving axially and flexibly. The separating apparatus allows for automatic adjustment of the meshing clearance between the reversal roller and the separation roller on the basis of the thickness of sheet-type media to be separated, thus effectively solving the problem of the sheet-type media being jammed or torn.