To analyze the skeletal characteristics of the open bite, the faces of normal occlusion and open bite were measured using a cephalogram. The factors which were greatly different form normal occlusion were selected. The effects of these factors on the incisal overbite and correlation on these factors were studied. The following results were obtained. 1. The 13 factors which comprised the characteristics of the open bite were obtained. (Table 5) 2. The cause and amount of the open bite were dependent on the skeletal angulation than skeletal length. 3. For determining the incisal overbite, most highly correlated sigle factor was the interincisal angle. 4. The correlation on the selected 13 factors which comprised the characteristics of the open bite was obtained. (Table 6) 5. The open bite was due to combination of various factors than due to single factor. (Table 3,4)