A living body state monitor apparatus includes: a living body information acquisition device to acquire living body information containing an electrocardiography waveform and a pulse waveform from a user; an irregular heartbeat detection section to detect an irregular heartbeat from the electrocardiography waveform; and a pulse wave feature quantity extraction section to extract a pulse wave feature quantity from a pulse wave corresponding to the irregular heartbeat. Further, a living body state determination section is included to determine a danger degree on user's living body state using both of (A) information on kind and/or continued time period of an irregular heartbeat detected by the irregular heartbeat detection section, and (B) a pulse wave feature quantity extracted by the pulse wave feature quantity extraction section, and/or a variation of the extracted pulse wave feature quantity.