Provided are a resistive random access memory (RRAM) and a manufacturing method thereof. The resistive random access memory includes multiple unit structures disposed on a substrate. Each of the unit structures includes a first electrode, a first metal oxide layer, and a spacer. The first electrode is disposed on the substrate. The first metal oxide layer is disposed on the first electrode. The spacer is disposed on sidewalls of the first electrode and the first metal oxide layer. In addition, the resistive random access memory includes a second metal oxide layer and a second electrode. The second metal oxide layer is disposed on the unit structures and is connected to the unit structures. The second electrode is disposed on the second metal oxide layer.