Mimitsu in Miyazaki prefecture is selected to grasp the seismic performance of traditional wooden houses. Seismic performance of 8 houses is evaluated based on microtremor measurements and structural investigation. As results, there are 2 types of traditional houses. One is the type with rooms in a line, and the other is with rooms in 2 lines. The traditional houses have skip floor structure, and the vibration mode is complicated. Yield base shear coefficients of houses with rooms in 2 lines are lower than those of houses with rooms in a line.