A 3D semiconductor device and a method of manufacturing the same are provided. The 3D semiconductor device includes a semiconductor substrate, an insulating layer formed on the semiconductor substrate, an active line including a source region and a drain region formed on the insulating layer, a gate electrode located on a portion of the active line, corresponding to a region between the source region and the drain region, and extending to a direction substantially perpendicular to the active line, and a line-shaped common source node formed to be electrically coupled to the source region and extending substantially in parallel to the gate electrode in a space between gate electrodes.