A radar image processing device comprising: a phase difference calculating unit for calculating a phase difference between a phase with respect to a first radio wave receiving point and a phase with respect to a second radio wave receiving point of each of a plurality of reflected signals present in each of pixels at corresponding pixel positions among a plurality of pixels included in a first suppression range and among a plurality of pixels included in a second suppression range, wherein the first suppression range is a region specified by a user, wherein the user specifies coordinates of vertices of a region using a man-machine interface, and wherein the second suppression range is a region specified by the user, wherein the user specifies coordinates of vertices of a region using a man-machine interface, or wherein the second suppression range is a range at the same position as the first suppression range, the first suppression range being a suppression range of reflected signals in a first radar image capturing an observation area from the first radio wave receiving point, the second suppression range being a suppression range of reflected signals in a second radar image capturing the observation area from the second radio wave receiving point; a rotation amount calculating unit for calculating each of phase rotation amounts in the pixels included in the second suppression range from each phase difference calculated by the phase difference calculating unit; and a difference calculating unit for rotating the phases in the pixels included in the second suppression range on a basis of the respective rotation amounts calculated by the rotation amount calculating unit, and calculating a difference between pixel values of pixels at corresponding pixel position among the pixels included in the first suppression range and the pixels obtained by the phase rotation included in the second suppression range. a phase difference calculating unit for calculating a phase difference between a phase with respect to a first radio wave receiving point and a phase with respect to a second radio wave receiving point of each of a plurality of reflected signals present in each of pixels at corresponding pixel positions among a plurality of pixels included in a first suppression range and among a plurality of pixels included in a second suppression range, wherein the first suppression range is a region specified by a user, wherein the user specifies coordinates of vertices of a region using a man-machine interface, and wherein the second suppression range is a region specified by the user, wherein the user specifies coordinates of vertices of a region using a man-machine interface, or wherein the second suppression range is a range at the same position as the first suppression range, the first suppression range being a suppression range of reflected signals in a first radar image capturing an observation area from the first radio wave receiving point, the second suppression range being a suppression range of reflected signals in a second radar image capturing the observation area from the second radio wave receiving point; a rotation amount calculating unit for calculating each of phase rotation amounts in the pixels included in the second suppression range from each phase difference calculated by the phase difference calculating unit; and a difference calculating unit for rotating the phases in the pixels included in the second suppression range on a basis of the respective rotation amounts calculated by the rotation amount calculating unit, and calculating a difference between pixel values of pixels at corresponding pixel position among the pixels included in the first suppression range and the pixels obtained by the phase rotation included in the second suppression range.