1. An apparatus for obtaining a pulse-wave-propagation-relating information of a living subject, comprising: a bifurcate-portion determining device which determines a bifurcate portion of an artery of the subject that is present under a skin of the subject; a pulse-wave-detect-portion determining means for determining, based on the determined bifurcate portion of the artery, a pulse-wave-detect portion of the artery from which a pulse wave is detected; a reference-point determining means for determining a reference point on the pulse wave detected from the determined pulse-wave-detect portion of the artery; and a pulse-wave-propagation-relating-information obtaining means for obtaining the pulse-wave-propagation-relating information of the subject based on the determined reference point of the pulse wave.