1. An apparatus for determining a standard pulse-wave-propagation-velocity-related value for a living subject, comprising: a blood-pressure measuring device for measuring a blood pressure of the subject; an age determining means for determining an age of the subject; and a standard-pulse-wave-propagation-velocity-related-value determining means for determining the standard pulse-wave-propagation-velocity-related value for the subject, based on the blood pressure of the subject measured by the blood-pressure measuring device and the age of the subject determined by the age determining means, according to a predetermined relationship between (A) (a1) blood pressure and (a2) age and (B) standard pulse-wave-propagation-velocity-related value.