Direction detection device, method of acquiring intensity difference table, direction detection method, and computer-readable storage medium

A direction detection device includes: antennas that receive a received wave; an intensity difference imparting unit that imparts intensity differences different depending on the received-wave arrival direction to intensities of the received wave; a storage unit that stores an intensity difference table in which the intensity difference between two of the antennas is associated with the received-wave arrival direction, for each combination of any two of the antennas; a detector that detects an intensity difference between the two antennas and a phase difference between the two antennas, of the received wave; an extractor that extracts, from the table, a received-wave arrival direction corresponding to the detected intensity difference, for each combination; a calculation unit that calculates a received-wave arrival direction corresponding to the detected phase difference; and a comparator that compares the extracted received-wave arrival direction with the calculated received-wave arrival direction to acquire a matched received-wave arrival direction.