A paper sheet storage unit (30,40) comprising: a casing; and a circulation unit (100,200) that is accommodated in the casing to receive paper sheets transported into the casing by operating upon reception of a drive force from a motor and feed paper sheets stored therein to outside of the casing, wherein the casing includes a guide member that is configured to serve as a guide at a time of attaching or detaching the circulation unit (100,200) to or from the casing by linearly and slidingly moving the circulation unit (100,200) with respect to the casing, and the circulation unit (100,200) includes a guided member (655A,675A,655B,675B), which is configure to detachably engage with the guide member, and to be guided to an installation completion position along the guide member in an engaged state, the circulation unit (100,200) includes a circulation drum (31,35,41,45) that is configured to spirally wind two tapes (T1-T4) around an outer periphery thereof in an overlapped state on each other and to feed each of the tapes (T1-T4) in a process of rotating in forward and reverse directions, and two bobbins (105,110,205,210) that are configured to respectively feed each of the tapes (T1-T4) to the outer periphery of the circulation drum (31,35,41,45) and to wind each of the tapes (T1-T4) in a process of rotating in forward and reverse directions, each of the tapes (T1-T4) forms a linear contact travel area (TA,TB) in which the tapes (T1-T4) come in contact with each other and transport a paper sheet, while placing the paper sheet therebetween, at a position immediately before moving to the outer periphery of the circulation drum (31,35,41,45), and a guide direction of the guide member to guide the guided member (655A,675A,655B,675B) is parallel to the contact travel area (TA,TB). a casing; and a circulation unit (100,200) that is accommodated in the casing to receive paper sheets transported into the casing by operating upon reception of a drive force from a motor and feed paper sheets stored therein to outside of the casing, wherein the casing includes a guide member that is configured to serve as a guide at a time of attaching or detaching the circulation unit (100,200) to or from the casing by linearly and slidingly moving the circulation unit (100,200) with respect to the casing, and the circulation unit (100,200) includes a guided member (655A,675A,655B,675B), which is configure to detachably engage with the guide member, and to be guided to an installation completion position along the guide member in an engaged state, the circulation unit (100,200) includes a circulation drum (31,35,41,45) that is configured to spirally wind two tapes (T1-T4) around an outer periphery thereof in an overlapped state on each other and to feed each of the tapes (T1-T4) in a process of rotating in forward and reverse directions, and two bobbins (105,110,205,210) that are configured to respectively feed each of the tapes (T1-T4) to the outer periphery of the circulation drum (31,35,41,45) and to wind each of the tapes (T1-T4) in a process of rotating in forward and reverse directions, each of the tapes (T1-T4) forms a linear contact travel area (TA,TB) in which the tapes (T1-T4) come in contact with each other and transport a paper sheet, while placing the paper sheet therebetween, at a position immediately before moving to the outer periphery of the circulation drum (31,35,41,45), and a guide direction of the guide member to guide the guided member (655A,675A,655B,675B) is parallel to the contact travel area (TA,TB).