A detachable adapter is adapted to be disposed in a handheld device and adapted to accommodate a memory card. The handheld device includes a socket connector. The memory card has a memory card terminal set. The socket connector has a socket body and a socket terminal set disposed at the socket body. The adapter includes an adapter body, and first, second and third terminal sets. The detachable adapter has an accommodating cavity in which the first terminal set is disposed. The second and third terminal sets are disposed on the adapter body. When the memory card is accommodated in the accommodating cavity, the first terminal set contacts the memory card terminal set. When the adapter body is assembled to the socket body, the second terminal set contacts the socket terminal set. When the adapter body is inserted into an electronic apparatus, the third terminal set contacts an apparatus terminal set.