The wave-making resistance could not be calculated quantitatively at present, though the excellent qualitative results have been obtained and one can design the ship form of minimum wave-making resistance through the wave-making resistance theory. Some points of the theory to be improved has been pointed out and by applying perturbation method the precise constructions of thin ship theory and slender ship theory have been devised, but the definite directions not yet found. The problems of a moving body which causes waves on the water surface might be very intricate and highly delicate. Recently T. F. Ogilvie paid attention to the composite properties of the problem, pointed out the defects of usual perturbation method and proposed a new method. Following him the author tries to explain the properties of ship wave in low speed range and to find out the points to be improved in the wave-making resistance theory by introducing an expansion of the solution appropriate to the characteristics of wave and ship motion. As a result, he asserts that usual linear theories can be applied only in high speed range and that the effect of finiteness of ship-breadth and the effect of wave diffraction have to be taken account into the boundary condition in low speed range. This conclusion confirms theoretical back-ground of some recent attempts to make satisfy the boundary condition exactly on the ship hull surface.