In order to reliably separate an unsterilized zone from a sterilized zone in a device for connecting a medical instrument, an adapter component set (28) is for connecting the medical instrument such as an endoscope to an unsterilized device having a timing pulley (27) included in a rotation mechanism for rotating the medical instrument. An adapter (47) holds the medical instrument. A separator (46) has a hollow cylinder shape for inserting the adapter therein. At least the inner surface of the separator is included in the sterilized zone, and the outer surface of the cylinder is connected to the pulley. As connecting parts for connecting a drape for isolating the device having the rotation mechanism from the sterilized zone, a pair of an outlet drape bearing (41) and an outlet drape bearing cover (42) and a pair of an inlet drape bearing (45) and an inlet drape bearing cover (44) are provided.
