An object is to provide a higher-performance and higher-reliability memory device and a semiconductor device provided with the memory device at low cost and with high yield. A semiconductor device of the invention has a memory element including an insulating layer and an organic compound layer between first and second conductive layers. When melting, an organic compound of the organic compound layer aggregates due to surface tension of the organic compound. By applying a voltage to the first and second conductive layers, writing to the memory element is carried out.