An object of the invention is to receive, with a high sensitivity, a radio
signal transmitted within a short time before a capsule endoscope reaches
the stomach of a subject and acquire, in a satisfactory state,
information on the interior of the subject such as image data picked up
by the capsule endoscope. The receiving apparatus according to the
invention includes a plurality of receiving antennas including a
specified receiving antenna for receiving a radio signal from a capsule
endoscope before the stomach is reached, a switching controller, an
arrival determining unit and a mode switching unit. The switching
controller performs a control operation for switching to and maintaining
the receiving antenna in an initial mode or a control operation for
switching to the receiving antennas in a normal mode. The arrival
determining unit determines whether the capsule endoscope has reached the
stomach or not. The mode switching unit instructs the switching
controller to perform the control operation for switching to the initial
mode, and upon determination that the stomach has been reached, gives the
instruction to perform the control operation for switching to the normal
mode.