A reverse field pinch (RFP) equilibrium configuration with helical magnetic axis is studied numerically over a wide range. The Grad-Shafranov equation is solved under the condition that the current flows along the magnetic field and the ratio of current to magnetic field is constant on every magnetic surface. Nested magnetic surfaces in the RFP are realized in this system; they are similar to those in a simple toroidal system. According to the direction of the helical winding, quite different RFP configurations are realized, depending on whether the current is parallel or antiparallel to the magnetic field. In the antiparallel case, the total plasma current is smaller than in the axisymmetric case although the ratio of current density to magnetic field is the same in both cases.