This paper describes numerical analyses method for shape identification problems of domains in which incompressible potential flow fields problems are defined. Reshaping was accomplished by the traction method that was proposed by one of the authors as a solution to domain optimization problems in which elliptic boundary value problems were defined. In previous paper, we applied the numemical analysis method based on the traction method to velocity prescribed problems in potential flow fields in which we chose the velocity square error norm between specified distribution and actual distribution for the objective functional. In this paper, we formulated a square error norm minimization problem of pressure distribution in stead of the velocity distribution based on Bernoulli's theorem and theoretically derived the shape gradient function. The validity of this numerical method was confirmed by the numerical results.