A body of a portable card reader/writer has open slots and includes key switches and a display located thereon. The IC card can be inserted either slot of the body. The end of the IC card inserted from one slot is positioned by a positioning member in the vicinity of the other slot. In this position, contacts of a connector of the IC card are electrically connected to contacts of an IC connector of the body. In addition, the body is provided with a positioning member which positions the IC card inserted from the other slot, and an IC connector.