Abstract: In order to decrease the amount of operation required for an operator to move a cursor and in order to allow the operator to distinctly view deviation of CRL (Crown Rump Length) of a fetus from a normal value, when an ultrasonic image of a fetus F is displayed and a first cursor C1 is positioned at the head (or the rump) of the fetus F, a second cursor C2 is initially displayed at a position which corresponds to a normal CRL obtained from GA (Gestation Age) estimated from the last menstruation date. When the second cursor C2 is moved and positioned at the rump (or the head) of the fetus F, the measured CRL and GA estimated therefrom are displayed.