In the theory of the wave resistance of submerged body, the condition of the water surface is always linearized by now, and this seems true as far as we treat of a deep immersed body. It is not fair, however, as we do of shallower immersion. The author gives a second approxmation to the water surface condition, and calculates the wave resistance and the vertical force acting on the submerged circular cylinder. The results are a) the effect of finite water surface disturbance rapidly decreases in the order (a/f) ⁴ as the immersion increases, where f is the immersion and a is the half radius of the cylinder, while the correction to the cylinder surface condition is of the order (a/f) ², and b) the both effects become comparable in the shallow immersion. (c. f. Figures.)