A medium processing device comprising: a processor having a tray (41 a) of a medium drive which has a storage for holding a plate-shaped medium and is capable of advancing and retreating; a medium transporting mechanism for performing transfer and reception of the medium with respect to the storage, a bump portion provided within the medium drive for contacting the tray to stop; and characterised in that it has: a restraining member (102A, 102B, 202A, 202B) for restraining an uplift movement of a front end of the tray that is projected to a position where the transfer and the reception of the medium is performed by the medium transporting mechanism, the restraining member has a restraining side (103, 207) that comes in contact with an upper portion of the front end of the tray that is projected to said position, and, the restraining side (103, 207) is upwardly inclined toward the processor, and the restraining member is movable so as to adjust a contact position between the restraining side (103, 207) and the upper portion of the front end of the tray and wherein the restraining member (102A, 102B) has a single long hole and is fixed to a side plate of the processing device by a screw inserted through the long hole, and the restraining member (102A, 102B) is disposed in a rack portion to slide along the rack portion, and is movable in an advance and retreat direction of the tray, or wherein the restraining member (202A, 202B) is pivotable about an axis in a width direction of the medium drive and the restraining member (202A, 202B) has a long hole having an arc shape and is fixed to a side plate of the processing device a screw inserted in the long hole. a processor having a tray (41 a) of a medium drive which has a storage for holding a plate-shaped medium and is capable of advancing and retreating; a medium transporting mechanism for performing transfer and reception of the medium with respect to the storage, a bump portion provided within the medium drive for contacting the tray to stop; and characterised in that it has: a restraining member (102A, 102B, 202A, 202B) for restraining an uplift movement of a front end of the tray that is projected to a position where the transfer and the reception of the medium is performed by the medium transporting mechanism, the restraining member has a restraining side (103, 207) that comes in contact with an upper portion of the front end of the tray that is projected to said position, and, the restraining side (103, 207) is upwardly inclined toward the processor, and the restraining member is movable so as to adjust a contact position between the restraining side (103, 207) and the upper portion of the front end of the tray and wherein the restraining member (102A, 102B) has a single long hole and is fixed to a side plate of the processing device by a screw inserted through the long hole, and the restraining member (102A, 102B) is disposed in a rack portion to slide along the rack portion, and is movable in an advance and retreat direction of the tray, the restraining member (102A, 102B) has a single long hole and is fixed to a side plate of the processing device by a screw inserted through the long hole, and the restraining member (102A, 102B) is disposed in a rack portion to slide along the rack portion, and is movable in an advance and retreat direction of the tray, or wherein the restraining member (202A, 202B) is pivotable about an axis in a width direction of the medium drive and the restraining member (202A, 202B) has a long hole having an arc shape and is fixed to a side plate of the processing device a screw inserted in the long hole. the restraining member (202A, 202B) is pivotable about an axis in a width direction of the medium drive and the restraining member (202A, 202B) has a long hole having an arc shape and is fixed to a side plate of the processing device a screw inserted in the long hole.