A radar apparatus is provided with: a transmission module for transmitting a transmission signal in which the frequency is changed over time; a reception module for receiving a radio wave returned by the transmission signal being reflected by an object as a reception signal; a frequency conversion module for generating an in-phase signal and a quadrature signal based on the reception signal; an amplitude signal generation module for generating an in-phase amplitude signal indicating the amplitude of the in-phase signal and a quadrature amplitude signal indicating the amplitude of the quadrature signal; a maximum value selection module for selecting the higher level of the in-phase amplitude signal and the quadrature amplitude signal as the maximum value signal; and a gain adjustment module for adjusting the gain of the reception signal based on the maximum value signal.