A radar device comprising: a transmission means that transmits at least a first transmission signal having a first frequency and a second transmission signal having a second frequency different from the first frequency; a reception means that receives the first transmission signal and the second transmission signal which are transmitted by the transmission means and are reflected by a plurality of objects as a first reception signal and a second reception signal; a quadrature demodulation means that performs quadrature demodulation with respect to each of the first reception signal and the second reception signal which are output from the reception means; a rotation means that rotates at least one of the first reception signal and the second reception signal which are subjected to the quadrature demodulation on an IQ plane in correspondence with a predetermined phase angle corresponding to a predetermined distance, and the first frequency or the second frequency; a processing means that adds or subtracts the first reception signal and the second reception signal of which at least one is rotated by the rotation means; and a detection means that detects the plurality of objects on the basis of a processing result of the processing means; wherein the processing means executes processing of subtracting the first reception signal and the second reception signal of which at least one is rotated by the rotation means so as to suppress a predetermined object among the plurality of objects; and wherein the radar device comprises: a storage means that stores information indicating a phase to be rotated with respect to each of the plurality of objects and that stores information about each object and a distance up to the object, wherein the rotation means rotates a phase of at least one of the first reception signal and the second reception signal on the basis of the information. a transmission means that transmits at least a first transmission signal having a first frequency and a second transmission signal having a second frequency different from the first frequency; a reception means that receives the first transmission signal and the second transmission signal which are transmitted by the transmission means and are reflected by a plurality of objects as a first reception signal and a second reception signal; a quadrature demodulation means that performs quadrature demodulation with respect to each of the first reception signal and the second reception signal which are output from the reception means; a rotation means that rotates at least one of the first reception signal and the second reception signal which are subjected to the quadrature demodulation on an IQ plane in correspondence with a predetermined phase angle corresponding to a predetermined distance, and the first frequency or the second frequency; a processing means that adds or subtracts the first reception signal and the second reception signal of which at least one is rotated by the rotation means; and a detection means that detects the plurality of objects on the basis of a processing result of the processing means; wherein the processing means executes processing of subtracting the first reception signal and the second reception signal of which at least one is rotated by the rotation means so as to suppress a predetermined object among the plurality of objects; and wherein the radar device comprises: a storage means that stores information indicating a phase to be rotated with respect to each of the plurality of objects and that stores information about each object and a distance up to the object, wherein the rotation means rotates a phase of at least one of the first reception signal and the second reception signal on the basis of the information. a storage means that stores information indicating a phase to be rotated with respect to each of the plurality of objects and that stores information about each object and a distance up to the object, wherein the rotation means rotates a phase of at least one of the first reception signal and the second reception signal on the basis of the information.