We had already reported the developed results on the hybrid type on board measuring method of directional wave spectrum. This method utilize the measured ship motions including relative wave heights and also uses information by radar images on board. By this method, ocean wave characteristics can be observed automatically and quantitatively on board of a running ship. But more data is required for evaluating this method. This time we report about the compared results with that of newly developed directional wave buoy, and also with the experimental results carried out in our towing tank for the improvement of the accuracy of our method.