Recently, the idea that the resistance change phenomenon is caused by oxidation/reduction of the filament formed in the transition metal oxide has been widely accepted. However, it is difficult to cause the forming equally for every cell in a high-density memory cell array. Therefore, the existence of the forming is high barrier for resistive random access memory (ReRAM) to be put into practical use. In this paper, the initial resistance dependence of the reset current and the distribution of the forming and set voltages were investigated for the forming-free ReRAM cells, which start with the reset process. As a result, it was clarified that the reset current is proportional to the reciprocal of initial resistance independently of the film thickness and the film formation temperature. In addition, it was suggested that there are two kinds of filaments in the forming-free ReRAM. One is the filament which is completely restored by the first reset process. The other continues to operate even after the first reset.