Patent ID: 8821046

Claim:
An accessory that is attachable to or detachable from an apparatus body having a plurality of contact terminals, the accessory comprising: a plurality of connection terminals configured to be connected to the plurality of contact terminals and configured to exchange a signal with the apparatus body, when the accessory is attached to the apparatus body; a lock lever that is operated between a lock position and a non-lock position and performs locking with respect to the apparatus body, when the lock lever is operated to the lock position; a detection activation section that detects a connection state of the plurality of contact terminals and the plurality of connection terminals, when the lock lever is operated to the lock position; and a fixing ring that has a rolling surface on which a click ball, which is coupled to the lock lever, is rolled in accordance with the movement of the lock lever, wherein the click ball is fitted into a first fitting recess on the fixing ring when the lock lever is operated to the non-lock position.