Externally hung type electronic equipment

An external electronic device (1) comprises an electronic device main body (2), a rotary operating unit (3) coaxially attached to the back end of the main body (2), and a USB terminal (4) attached to the front end (2a) of the main body (2). An electronic device to which the external electronic device (1) is to be connected, such as a personal computer (5), has a USB socket (51). When the USB terminal (4) is plugged in the USB socket (51), the external electronic device (1) is connected to the personal computer (5). When the external electronic device (1) is connected, the rotary operating unit (3) can be rotated so that a fingertip may be easily placed on the fingertip placing surface (6). Irrespective of the position and orientation of the USB socket (51), the fingertip placing surface (6) of the external electronic device can be brought into a state that the finger chip can be easily placed thereon.