The various configurations of thin-shaped bevel gears are used widely for such as main reduction gear of the helicopter and hovercraft. But, the reasonable and concise guide to design of these bevel gears is not yet obtained, since the tooth of bevel gear has complex form. The purpose of this investigation is to establish the design guide and to propose the desirable configuration for thin-shaped straight bevel gears. In this report, the desirable configuration is examined experimentally, by clearing up the effect of web and rim thicknesses, rim support condition upon the load distribution and the root stress distribution along the tooth trace. The results are summarized as follows. (1) The crowning of tooth trace exerts a significant effect on the root stress distribution of thin-shaped bevel gear. (2) As the desirabe configuration of thin-shaped bevel gear, it is to be recommended from viewpoint of root stress that the rim is supported at the heel side of tooth trace.