In a detection and ranging apparatus that performs direction-of-arrival estimation using a sensor array and that enlarges an effective aperture using a plurality of transmitting sensors, adverse effects associated with time division switching are eliminated, achieving high-accuracy measurement. A transmitter wave is spread in modulators by using mutually orthogonal codes, and the resulting transmitter waves are radiated from two transmitting sensors. Signals received by receiving sensors are each split by a splitter into two parts, which are then respectively despread in a demodulator by using the same codes as those used in the transmitter.