PURPOSE: To electrically connect a connection medium and a medium to be connected.

CONSTITUTION: In an automatic attachable/detachable mechanism, when a notebook PC having a connector 4 with a relatively wide width is connected to a personal computer having a connector 5 capable of being connected with the connector 4, if the note book PC on the tray is crammed, a motor 9 is driven and the tray automatically moves in the insertion direction, resulting in pulling the note book PC in. The terminals on both ends of the connector 4, that is, 1 pin and 200 pin are pulled up to +5V. The 1 pin and the 200 pin of the connector 5 are grounded. After the connection by the automatic attachable/detachable mechanism, if at least one of the 1 pin or the 200 pin is not connected, the motor is rotated in the reverse direction and moves in the exhaust direction. Thus, the note book PC is exhausted and the note book PC is connected again.