For the fundamental study of aerodynamic heating of winged vehicle and space planes in hypersonic flow the detailed structure of three-dimensional shock wave/turbulent boundary layer interaction region induced by sweptback sharp fins are investigated carefully by oil flow technique and pressure distribution. The major objectives of the present study are to study the effects of the shape of the leading edge of the fin to the flow fields on the body and to study the effect of the sweep angle of the leading edge of the fin to the interaction region. Also aerodynamic heating phenomena in the flow fields are investigated by using a new technique. For the measurements a new method of measuring heat flux developed by the present authors are used. The new method is based on a new type of thin-film heat transfer gauge with high spatial resolution and fast response. The results suggest the effects of the shape of the leading edge to the flow fields are quite significant and the sweep of the leading edge of the fin to freestream is quite important to reduce the interaction region.