End pulse wave measurement means 3 measures an end pulse wave. Heart rate computation means 16 computes a heart rate per unit time from the measured end pulse wave. Autonomic nervous balance computation means 17 defines the heart rate per unit time as HR, and calculates an approximate value HFa of the autonomic nervous balance by Equation (1) below: HFa=k1*HR3+k2*HR2+k3*HR+k4&emsp；&emsp；Equation (1) where k1=&minus；0.0003, k2=0.0796, k3=&minus；8.5795, and k4=325.3. This makes it possible to obtain autonomic nervous balance from the heart rate HR. Hence, the autonomic nervous balance is determined through measurement for a short period.
