PROBLEM TO BE SOLVED: To receive radio signals transmitted by a capsule type endoscope in a short period of time until the endoscope reaches the stomach of a subject, with high sensitivity and to acquire image data imaged by the capsule type endoscope in an excellent state.SOLUTION: The receiver includes: a plurality of reception antennas 3a-3h including a specific reception antenna 3a for receiving the radio signals from the capsule type endoscope 2 until reaching the stomach of the subject a changeover control part 33 for performing the changeover control of an initial mode for switching to the reception antenna 3a and maintaining it or the changeover control of a normal mode for switching to the remaining reception antennas 3b-3h a reach determination part 38a for determining whether the capsule type endoscope 2 has reached the stomach of the subject and a mode switching part 38b for instructing the changeover control of the initial mode to the changeover control part 33, and switching the initial mode to the normal mode and instructing the changeover control of the reception antennas when it is determined that the endoscope 2 has reached the stomach of the subject.
