Provided are a capacitorless DRAM (dynamic random access memory) and a fabrication method thereof. In a capacitorless DRAM, a pair of cylindrical auxiliary gates is formed within a bulk substrate. Thus, a volume of a channel body formed at a region where the cylindrical auxiliary gates contact with each other can be increased, while an area of a junction region where the channel body contact source and drain regions can be reduced. As a result, capacitance of the channel body can be increased, and a generation of leakage current through the second junction region can be reduced. The application of a back bias to the cylindrical auxiliary gates can improve a charge storage capability of the channel body.