A cardiac signal processing apparatus includes: a unit for acquiring, from a heartbeat sensor, cardiac signals relating to heartbeats of a subject a low-pass filter for allowing passage of those cardiac signals having a first predetermined frequency or lower, among the cardiac signals higher harmonic noise acquisition unit for acquiring harmonic signals of low-frequency noise by performing high frequency extrapolation on the signals output from the low-pass filter a high-pass filter for allowing passage of those cardiac signals having a second predetermined frequency or higher, among the cardiac signals and higher harmonic noise removal unit for removing the harmonic signals of low-frequency noise from the signals output from the high-pass filter. It is thus made possible to remove noise from the cardiac signals and to obtain desirable heartbeat detection characteristics.
