A radar apparatus mounted on a moving body comprising: a signal transceiver that receives one or more radar signals reflected by one or more reflection points of one or more targets located in a scan range with a plurality of antennas; detection circuitry that detects an azimuth angle of the one or more reflection points of the one or more targets on the basis of a correspondence between a phase difference among the plurality of antennas and a stored azimuth angle and wherein the phase difference being observed in the scan range among the plurality of antennas, the observed phase difference being determined on the basis of the one or more radar signals; and characterized by: a calculation circuitry that selects, on the basis of the detected azimuth angle, from the one or more reflection points one or more second reflection points located in a second range that differs from a first range including a central axis on which the phase difference among the antennas is zero and calculates a second azimuth angle error on the basis of the azimuth angle of each of the one or more selected second reflection points and a true value of the azimuth angle of each of the one or more selected second reflection points, wherein the true value is input from a connected image pickup apparatus external to the radar apparatus; and correction circuitry that corrects the correspondence on the basis of the observed phase difference among the antennas and the second azimuth angle error. a signal transceiver that receives one or more radar signals reflected by one or more reflection points of one or more targets located in a scan range with a plurality of antennas; detection circuitry that detects an azimuth angle of the one or more reflection points of the one or more targets on the basis of a correspondence between a phase difference among the plurality of antennas and a stored azimuth angle and wherein the phase difference being observed in the scan range among the plurality of antennas, the observed phase difference being determined on the basis of the one or more radar signals; and characterized by: a calculation circuitry that selects, on the basis of the detected azimuth angle, from the one or more reflection points one or more second reflection points located in a second range that differs from a first range including a central axis on which the phase difference among the antennas is zero and calculates a second azimuth angle error on the basis of the azimuth angle of each of the one or more selected second reflection points and a true value of the azimuth angle of each of the one or more selected second reflection points, wherein the true value is input from a connected image pickup apparatus external to the radar apparatus; and correction circuitry that corrects the correspondence on the basis of the observed phase difference among the antennas and the second azimuth angle error. a calculation circuitry that selects, on the basis of the detected azimuth angle, from the one or more reflection points one or more second reflection points located in a second range that differs from a first range including a central axis on which the phase difference among the antennas is zero and calculates a second azimuth angle error on the basis of the azimuth angle of each of the one or more selected second reflection points and a true value of the azimuth angle of each of the one or more selected second reflection points, wherein the true value is input from a connected image pickup apparatus external to the radar apparatus; and correction circuitry that corrects the correspondence on the basis of the observed phase difference among the antennas and the second azimuth angle error.