The domain shape formation of monolayers comprised of polar molecules with the orientational deformation of spontaneous polarization is investigated by viewing this problem as electrostatic charge effect. The orientational deformation contributes to the domain free energy as the spontaneous curvature, Frank elastic energy, and spontaneous splay, which originate from the effect of diagonal and off-diagonal components of capacitance matrix. Shape equation is extended by introducing the concept of "curvature of polarization" to take into account the spontaneous curvature. It is exemplified that the spontaneous curvature is reasonably understood as the shape formation to optimize the off-diagonal component of electrostatic energy.