In a semiconductor device having a multi-bridge-channel, and a method for fabricating the same, the device includes first and second semiconductor posts protruding from a surface of a semiconductor substrate and having a source and a drain region, respectively, in upper side portions thereof, channel semiconductor layers connecting upper side portions of the first and second semiconductor posts, a gate insulation layer on the channel semiconductor layers and the semiconductor substrate, the gate insulation layer surrounding at least a portion of the channel semiconductor layers, a gate electrode layer on the gate insulation layer to enclose at least a portion of a region between the channel semiconductor layers, and junction auxiliary layers formed between the channel semiconductor layers, the junction auxiliary layers contacting the gate electrode layer and upper side portions of the first and second semiconductor posts, and having a same width as the channel semiconductor layers.