An autonomic nerve index calculation system for calculating an autonomic nerve index of a living body, the autonomic nerve index calculation system comprising: a pulse wave waveform generation unit configured to generate pulse wave waveform data using at least one pulse wave signal of the living body; a band-pass filter configured to filter the generated pulse wave waveform data in at least one predetermined frequency band; a complex number conversion unit configured to convert the filtered pulse wave waveform data into a complex number by Hilbert transformation and calculate pulse wave complex waveform data of the at least one frequency band; and an index calculation unit configured to calculate the autonomic nerve index of the living body in the at least one frequency band based on the calculated pulse wave complex waveform data, wherein the index calculation unit is configured to: calculate at least one distribution of an instantaneous amplitude and an instantaneous frequency at predetermined time intervals, wherein the instantaneous amplitude corresponds to an absolute value of an amplitude term of the pulse wave complex waveform data and the instantaneous frequency corresponds to a time differential value of a phase term of the pulse wave complex waveform data; and calculate at least one of a distribution coefficient of the instantaneous amplitude based on a distribution of the instantaneous amplitude and a distribution coefficient of the instantaneous frequency based on a distribution of the instantaneous frequency as the autonomic nerve index. a pulse wave waveform generation unit configured to generate pulse wave waveform data using at least one pulse wave signal of the living body; a band-pass filter configured to filter the generated pulse wave waveform data in at least one predetermined frequency band; a complex number conversion unit configured to convert the filtered pulse wave waveform data into a complex number by Hilbert transformation and calculate pulse wave complex waveform data of the at least one frequency band; and an index calculation unit configured to calculate the autonomic nerve index of the living body in the at least one frequency band based on the calculated pulse wave complex waveform data, wherein the index calculation unit is configured to: calculate at least one distribution of an instantaneous amplitude and an instantaneous frequency at predetermined time intervals, wherein the instantaneous amplitude corresponds to an absolute value of an amplitude term of the pulse wave complex waveform data and the instantaneous frequency corresponds to a time differential value of a phase term of the pulse wave complex waveform data; and calculate at least one of a distribution coefficient of the instantaneous amplitude based on a distribution of the instantaneous amplitude and a distribution coefficient of the instantaneous frequency based on a distribution of the instantaneous frequency as the autonomic nerve index. calculate at least one distribution of an instantaneous amplitude and an instantaneous frequency at predetermined time intervals, wherein the instantaneous amplitude corresponds to an absolute value of an amplitude term of the pulse wave complex waveform data and the instantaneous frequency corresponds to a time differential value of a phase term of the pulse wave complex waveform data; and calculate at least one of a distribution coefficient of the instantaneous amplitude based on a distribution of the instantaneous amplitude and a distribution coefficient of the instantaneous frequency based on a distribution of the instantaneous frequency as the autonomic nerve index.