To understand and evaluate structural characteristics of typical traditional wood houses in Kyoto, structural styles and details of thirty traditional wood houses were investigated. The wooden frames, seismic structural elements and joints are clarified. From investigation results, it is found that these wood houses have significantly different base shear coefficients in the directions; in particular, the base shear coefficients in the ridge direction are low. From the seismic performance analyses, it is suggested that the seismic reinforcement is needed for many traditional wood houses.