The present disclosure provides a semiconductor device. The semiconductor device includes an active region, a plurality of channel layers, gate electrodes, a source/drain region, and a contact structure. The active region is disposed on a substrate and extends in a first direction. The plurality of channel layers are disposed on the active region to be spaced apart from each other vertically. The gate electrodes are disposed on the substrate, intersecting the active region and the plurality of channel layers, extending in a third direction, and surrounding the plurality of channel layers. The source/drain region is disposed on the active region on at least one side of the gate electrodes, and contacting the plurality of channel layers. The contact structure is disposed between the gate electrodes, extending in the second direction, and contacting the source/drain region.