A capsule endoscope system including: a capsule endoscope including an imaging sensor configured to capture an image of inside of a subject at a changeable imaging frame rate and generate an image signal, and an image transmitter configured to transmit a wireless signal including the image signal and a receiving device including a first and a second antennas configured to receive the wireless signal, a receiver configured to detect a first reception intensity and a second reception intensity, a controller configured to generate a first instruction signal that changes the imaging frame rate to a first value higher than an initial value that is set in advance when the first or the second reception intensity satisfies a predetermined condition, and a transmitter configured to wirelessly transmit the first instruction signal to the capsule endoscope.
