The allowable toe pressure of 50 tf/m2 which has been determined empirically often restricts the design of caisson type composite breakwaters constructed in deep water area. A series of large scale model tests were carried out to examine the bearing capacity of rubble mounds including the limit toe pressure. Eccentric and inclined force was loaded on a steel plate 1m wide, 2m long and 20cm thick placed on the surface of the graval mound in a steel tank 2m wide, 6m long and 2.5m deep. Gravels having diameters of 0.5 to 2.5 cm were used so that the test equipment was geometrically similar; the scale of length was about 1/20. The test conditions varied were eccentricity and inclination of loads and the shape of granvel mound. The test results showed clear influences of the test conditions on the behavior of the mound surface. It was found that the bearing capacity of model mounds were much larger than expected. Some causes for these results were examined; these include the difference in internal friction angles between observed and expected ,and the resistance by side wall friction. Besides, no evidence was observed that the limit toe pressure was independent of test conditions.