A device differentiates a living body, the device including a circuit. The circuit acquires first N reception signals, each of the first N reception signals has been received at respective one receiver out of N receivers, which are arranged to surround a periphery of a predetermined range, using respective reception antenna elements of the N receivers during a predetermined period. The circuit also calculates a plurality of correlation coefficients based on a teacher signal, stored in the memory, and the first N reception signals. The circuit further determines that the living body and a subject living body are identical to each other when a correlation coefficient, included in the plurality of correlation coefficients, is included in a predetermined value range.