The calculation of response and limit Strength for traditional Japanese wooden structure often causes the structure collapse at 1st floor. To prevent the structure collapse at a given floor, the equation of every story deformation angle is required. The continuous column of heavy timber over than 180 mm square is proposed to average story deformation angles. In this paper, the calculation method for the section size of continuous columns is proposed. Results are as follows: 1) The calculation method for the section size of continuous columns consists of 2 equations: the equation for flexure capacity and the equation of difference between deformation angles. 2) The proposed method lessens the negative gradient of a Sa-Sd curve.