A transmitting and receiving apparatus (2) that transmits a radio signal to a capsule endoscope includes: a transmitting level determining unit (25) disposed near a transmitting resonance circuit (22); a frequency controller (26) that controls an oscillation frequency based on a result of determination executed by the transmitting level determining unit (25); and a frequency variable oscillator (16) that changes the oscillation frequency, based on the control of the frequency controller (26). By changing the oscillation frequency so that a transmission level becomes large, the oscillation frequency can be changed so as to decrease a frequency difference between the oscillation frequency and the resonance frequency of the resonance circuit (22) that changes along a variation in a self inductance value of a coil (24).