In order to be able to accurately identify a signal source using a radio wave-type non-contact radio wave sensor without being affected by surrounding environmental vibrations, a first environmental information associated with a biological information detected by a first non-contact sensor, and a second environmental information associated with a biological information detected by a second non-contact sensor are subtracted by a first subtractor, and the signal from the first subtractor is added to a first adaptive filter and extracted as a noise source. Next, the noise source signal extracted by the adaptive filter is subtracted from the first environmental information associated with the biological information detected by the first non-contact sensor by a second subtractor, and the position of a subject is identified in accordance with the magnitude of the signal from the second subtractor.
