Formulations and numerical results for optimal shape design of a body located in the incompressible Stokes fluid flow are presented. The study is based on an optimal control theory. The optimal state is defined by the reduction of drag forces subjected to the body. The cost functional should be minimized satisfying the Stokes equations. The Shape sensitivity analysis of the cost functional was derived based on the adjoint method. For the numerical study, the optimal shape of the body which has a circular shape as an initial state can be finally obtained as the streamlined shape.