The driving mechanism has an instrument body formed with a recording medium inserting slot for inserting a recording medium into the instrument body. The driving mechanism moves a first operation unit and a second operation unit between a first position for covering the recording medium inserting slot and a second position for exposing the recording medium inserting slot. The driving mechanism includes a first turnable supporting member turnably fitted to the instrument body for supporting the first operation unit, a first drive device for turning the first turnable supporting member, a second supporting member for supporting the second operation unit, a second turnable supporting member turnably fitted to the instrument body for supporting the second operation unit, and a second drive device for turning the second turnable supporting member. The second drive device supports the second supporting member movably in directions along which the recording medium is inserted and removed through the recording medium inserting slot of the instrument body. The first drive device turns the first turnable supporting member to move the first operation unit between the first position and the second position. The second drive device moves the second supporting member and turns the second turnable supporting member to move the second operation unit between the first position and the second position.