We have developed the automatic tracking method for regional myocardium with high accuracy on ultrasonic RF echo signal. Previously we proposed "correlation method with confidence (CMC)". However, the ability of the tracking method is insufficient for the RF signals of some subjects. This paper describes a study on the improvement in accuracy of the automatic tracking (CMC). The tracking method employs the correlation coefficients at a position as the degree of confidence of the tracking for a specified observing point, that is, it employs the position obtained by hierarchical correlation method for an observing points if the correlation coefficient of the observing point is high, and it employs the mean moved position of two nearby observing points at the same time if the correlation coefficient of the observing point is low. However, we found the unfortunate case for the tracking method, that is, the fact that the many points have low correlation coefficients at the same time. We found that the large movement of myocardium causes the tracking error for CMC.