The inclination to higher ship speed is advancing in recent years. Among others, expectation is great from high speed vessels supporting short distance transportation of highly value added products. While the studies on supercavitating propeller and others having been made in late years, their study objects were limited mainly to propeller's propulsive performance. The root cavitation erosion, which is frequently sustained by high speed vessels, is the problem involved not only with deterioration of the propeller's durability or life but also with hindranceof the vessel's operational safety. Despite the fact that the study on its generation mechanism was made, and several countermeasures with some appendages against the phenomenon were devised, no development has been made yet on a method for an effective prevention of the phenomenon with any designing improvement applied to a propeller itself. If the root erosion generation peculiar to high speed vessels could be prevented, we understand that the relative method will surely comply with the need by the shipping industry. Under such a background as above, this study aims at development of the new propeller effective to prevention of root erosion. Our concept of the new blade section for the root erosion prevention is described in the concrete, to be followed by the description about verification of its effectiveness by means of model test and actual vessel test, and successful development of the new propeller with preventive effectiveness against the root erosion for high speed vessels.