This paper reports the results of our research on seismic behavior of traditional wooden houses with L-shaped plan, Magariya, in Fukushima prefecture. First, to figure out the structural characteristics and vibration characteristics, we investigated the seismic elements and current state of the Magariya. We understood that main part and attached part of the building may not move as one structure. In addition, we estimated seismic performance and eccentricity of Magariya by limit strength calculation.