Abstract: A card connecting adapter for connecting, to a card slot of one standard, a card of the other standard. The adapter has a first connecting portion corresponding to the card slot, a second connecting portion corresponding to the card, a plurality of terminals for electrical connection to the card, shutter mechanism, and locking mechanism. The shutter mechanism has a shutter member displaceable between a protecting position where the terminals are protected from the exterior and a connecting position where the terminals are exposed, and interlocking mechanism for displacing the shutter member in synchronization with operations for mounting/removing the card on/from the second connecting portion. The locking mechanism includes a locking spring member that is disengaged from the shutter member upon being deformed by the mounting of the card, and that is returned to an engaged state with the shutter member by removal of the card.