In a calibration apparatus, which calibrates the phases of main signals input to each of the antenna elements of an array antenna, a calibration signal generation portion generates calibration signals, which are combined with main signals. An RF switch alternately inputs to a wireless receiving portion the signals radiated from other antenna elements via a first antenna element, and the signals radiated from other antenna elements via a second antenna element, and causes demodulation. The calibration detection portion detects calibration signals from the demodulated signals, and the weight generation portion uses the detected calibration signals to calculate calibration weights, which are set in the phase shifter, to control the phases of main signals for input to each antenna element.