PURPOSE: To execute the positioning of a communication coil regardless of a shape, to execute communication between one high order device and plural portable information devices simultaneously and to execute the communication between the portable information devices as well by hollowing out a part corresponding to the central part of the communication coil in a case and obtaining a shape, into which a core for communication can be put.

CONSTITUTION: A communication coil 4a is fit to the upper central part of a case 2 in an portable information device 1 and the communication coil 4a is covered with the case 2 in a doughnut shape. Then, the center of the coil is cavity. A core 8 for communication is fit to the center of a communication coil 4b in a high order device 6 and the portable information device 1 can be hung with being put into a coil hole 9 of the portable information device 1. Accordingly, the positioning of the communication coil for the portable information device 1 and high order device 6 can be executed only by putting the core 8 for communication. Thus, transferring pocket for communication is eliminated and the communication from one high order device to the plural portable information devices can be simultaneously executed and the communication between the portable information devices can be executed as well.