PROBLEM TO BE SOLVED: To provide a new system for appropriately setting a measuring region for computing an evaluation value of thickness or the like in an apparatus for measuring the cartilage of a knee joint using ultrasonic waves.SOLUTION: Data of a reference shape model 60 showing the standard shape of a femur distal end is prepared. The data include information on an alignment reference of a ridgeline 62 or the like in the standard shape and information on the measuring region 64. An ultrasonic diagnostic apparatus determines the alignment reference shape of the ridgeline or the like from the three-dimensional shape 70 of the cartilage obtained by ultrasonic measurement, and aligns the reference shape model 60 and the three-dimensional shape 70 of the cartilage to obtain the best coincidence of shapes and positions of the alignment reference of the reference shape model 60 and the alignment reference of the three-dimensional shape 70 of the cartilage. In the thus aligned state, the measuring region 64 set to the reference shape model 60 is applied to the three-dimensional shape 70 of the cartilage to set the measuring region for the three-dimensional shape 70 of the cartilage.
