A plurality of transmission antennas include Nt1 transmission antennas arranged in a first direction and Nt2 transmission antennas arranged in a second direction orthogonal to the first direction, a plurality of reception antennas include Na1 reception antennas arranged in the first direction and Na2 reception antennas arranged in the second direction. In the first direction, an inter-element space between any two of the Nt1 transmission antennas and an inter-element space between any two of the Na1 reception antennas are each a value which is a product of a first space and an integer and are all values different from each other, and in the second direction, an inter-element space between any two of the Nt2 transmission antennas and an inter-element space between any two of the Na2 reception antennas are each a value which is a product of a second space and an integer and are all values different from each other.