1. A radar apparatus comprising: an antenna for transmission and reception configured to repeatedly emit transmission beams while changing azimuth of emission and to receive reflected echo from reflecting bodies; an analog-to-digital converter configured to convert analog signal corresponding to echo signal received by the antenna to digital data; a memory configured to store the digital data obtained through conversion in the analog-to-digital converter in association with distance from the antenna and azimuth for the antenna to rotate; processing circuitry configured to convert a value of data of interest to be processed, of the digital data read from the memory, to a value based on values of the data of interest and peripheral data in a periphery along the distance direction of the data of interest; and a display screen configured to show a display based on the digital data filtered by the processing circuitry, the processing circuitry being further configured to change a range of the peripheral data used for a filter processing according to the distance from the antenna in association with the data of interest.