This disclosure relates to a signal processing device, a signal processing method, and a receiving device that are capable of detecting response information at a high degree of accuracy from a carrier signal that is load-modulated based on the response information. A positive DC generating unit 61 generates a positive threshold based on a load-modulated carrier signal. A positive selecting unit 62 compares the voltage of the carrier signal with the positive threshold, and outputs the value of the larger one to an adding unit 65. A negative DC generating unit 63 generates a negative threshold based on the load-modulated carrier signal. A negative selecting unit 64 compares the voltage of the carrier signal with the negative threshold, and outputs the value of the smaller one to the adding unit 65. The adding unit 65 adds the output of the positive selecting unit 62 and the output of the negative selecting unit 64, and outputs the addition result to an IQ detecting unit 53. As a result of the combining, a signal that has smaller Vpp than that of the original carrier signal and maintains the fluctuation portions of the voltage is obtained. This disclosure can be applied to non-contact communication systems.