A heartbeat signal processor includes a first and second electrodes to obtain a first and second heartbeat signals, a DC voltage calculating unit and an AC amplitude calculating unit to calculate first and second average DC voltage values of direct-current components and first and second average AC amplitude values of alternate-current components in the first and second heartbeat signals, a correlation coefficient calculating unit to calculate a correlation coefficient between the alternate-current components in the first and second heartbeat signals, an amplification factor setting unit to set an amplification factor on the basis of the first and second average DC voltage values, the first and second average AC amplitude values, and the correlation coefficient, and a signal generating unit to generate a differential heartbeat signal by amplifying the first or second heartbeat signal on the basis of the amplification factor and calculating a difference between the first and second heartbeat signals.
