A condition for determining that an examination by a capsule endoscope 3 (body insertable device) completes is set in advance. When a predetermined time period has passed since the examination starts, and when received electric-field strength of receiving antennas A1 to An detected during a predetermined time period is not higher than a predetermined value, the examination is determined to have been completed. An examination completion determining unit C1 determines whether the condition is satisfied or not. According to the result of determination, a notification controller C2 makes a notifying unit 15 notify that the examination completes, and a power supply controller C3 stop power supply to a radio unit 2a. Thus, unnecessary power consumption is prevented and the completion of the examination by the body insertable device is recognized.