Measurement data, which is obtained by measuring a cross section of the body with an ultrasonic wave, is acquired based on a received signal of an ultrasonic wave transmission and reception unit configured to transmit and receive an ultrasonic wave to and from a blood vessel through the surface of the body, the blood vessel having a part satisfying predetermined tissue conditions. The part is detected based on the acquired measurement data. Then, it is detected that the ultrasonic wave transmission and reception unit has moved on the surface of the body along the longitudinal direction of the blood vessel and has reached a predetermined position for performing predetermined vascular function measurement, from the detection of the part, based on the measurement data.
