the surface of the human body as depicted in fig2 eight receiving electrodes are respectively installed on the surface of the human body for example the chest the navel an upper portion of the back a lower portion of the back the axillae and the sides when current generated by electric potential difference between transmitting electrodes 11 of a capsule type endoscope 10 reaches plural receiving electrodes through the human body a voltage is induced between the two receiving electrodes in proportion to the current and distance between the two receiving electrodes with reference to fig2 considering receiving electrodes 1 and 2 as a pair of receiving electrodes the greatest voltage is detected between receiving electrodes 1 and 2 that is because an aligning direction of the transmitting electrode 11 is coincided with that of the receiving electrodes 1 and 2 and also distance between the capsule type endoscope 10 and the receiving electrodes is the shortest on the other hand considering receiving electrodes 3 and 4 or receiving electrodes 7 and 8 as a pair of receiving electrodes a voltage is not detected between the receiving electrodes that is because an aligning direction of the transmitting electrode 11 of the capsule type endoscope 10 is vertical to an aligning direction of the receiving electrodes in addition considering receiving electrodes 5 and 6 as a pair of receiving electrodes voltage between the receiving electrodes 5 and 6 is less than that between the receiving electrodes 1 and 2 that is because an aligning direction of the transmitting electrode 11.