A memory card includes a card body, an interface terminal and an attachment mechanism for detachably mounting the card to an adaptor of an electronic device. The interface terminal is disposed at a central portion of a major surface of the card body. The attachment mechanism is located at an outer peripheral portion of the card body that surrounds the central portion. The adaptor has a recess whose shape complements that of the major surface of the card body, and socket exposed at a central portion of the bottom of the recess. Thus, the memory card may be inserted face down into the adaptor.