To provide an arrival direction estimating device capable of estimating an arrival direction of an arrival wave regardless of accuracy of switchable directivity.

An array antenna 10 receives L arrival waves by switching its beam pattern into a plurality of beam patterns. A direction estimating means 30 calculates a correlation matrix in which inter-element connection of antenna elements 1-7 is reflected on the basis of a received signal received by the array antenna 10, and also, calculates a received power spectrum of the array antenna 10 on the basis of the calculated correlation matrix and a steering vector of the array antenna 10. The direction estimating means 30 estimates a direction of appearing the peak in the received power spectrum as the arrival direction of the L arrival waves.