Unconventional way of handling the perturbative series is presented with the help of Heaviside transformation with respect to the mass. We apply Heaviside transform to the effective potential in the massive Gross-Neveu model and carry out perturbative approximation of the massless potential by dealing with the resulting Heaviside function. We find that accurate values of the dynamical mass can be obtained from the Heaviside function at finite orders where just several diagrams are incorporated. We prove that our approximants converge to the exact massless potential in the infinite order. Small mass expansion of the effective potential can also be obtained in our approach.