To provide a determining method and an evaluation system for the degree of arteriosclerosis in which no burden is imposed on a patient and which exhibits both of precision and simplicity.

The determining method for the degree of arteriosclerosis uses the measured value of the frequency of the blood vessel sound as an index. The evaluation system and the apparatus for the degree of arteriosclerosis use the determining method. A technique is provided which measures the frequency of the blood vessel sound (Korotkoff sound) by attaining the simplicity and speediness of measuring and which uses increase in the peak frequency of the power spectrum of the frequency of the blood vessel sound with the advance of the arteriosclerosis as an index.