A first calculation part (32) receives phase characteristics (Pa(f) and Pb(f)) output from frequency conversion parts (30a, 30b), calculates a propagation time difference on the basis of the phase difference of the high frequency components of the two characteristics, and calculates a pulse wave propagation speed by dividing the difference in distance of a vascular route to each measurement location from the heart. In addition, a second calculation part (38) calculates a pulse wave propagation speed by dividing the difference in the above-mentioned distance by the difference in when pulse wave waveforms, which respectively correspond to measurement signals (Pa(t), Pb(t)) and are drawn on a time axis, appear at a predetermined location. A comparison part (40) compares these pulse wave propagation speeds and when the ratio thereof is outside a predetermined range, the comparison part (40) outputs, to a display processing part (42), an evaluation result indicating the possibility of a predetermined pathological change existing on the vascular route.