The nonlinear programming is now used in the field of structural design in general, but it has possibilities of application to other engineering problems. In this paper, the authors apply the SUMT (Sequential Unconstrained Minimization Technique) method to the hull form design so as to make the resistance minimum under several kinds of the constraints. The total resistance is expressed by the sum of the Michell integral and the plank friction both of which are multiplied by suitable weighting factors. Series 60 model is employed as the basis of a numerical example. The fore body shape is improved by the present technique.