Polarization direction measuring device, method of acquiring intensity ratio tables, polarization direction measuring method, and computer-readable storage me

A device 1 for measuring a polarization direction of a linearly polarized received wave using circularly polarized antennas. The process involving an intensity ratio providing unit that provides intensity ratios different depending on an arrival direction for the received wave. A storage unit 11 that stores a first table T1 in which an intensity ratio of a vertically polarized component of the received wave between two of the antennas is associated with the arrival direction and a second table T2 in which an intensity ratio of a horizontally polarized component of the received wave between the two antennas is associated with the arrival direction. A detector 10 that acquires an intensity ratio of the received wave and an acquiring unit 12 that acquires the arrival direction. An arithmetic unit 13 that calculates the polarization direction of the received wave based on the acquired intensity ratio and the intensity ratios of the vertically and horizontally polarized components.