A ReRAM device includes an interlayer dielectric (ILD), a lower conductive plug, a resistance-switching element (RSE) and an upper conductive plug. The ILD has an upper surface. The lower conductive plug is disposed in the ILD, and has a top surface lower than the upper surface. The RSE is disposed above the top surface and electrically contacts with the top surface. The upper conductive plug is disposed above the RSE and electrically contacts with the RSE.