A semiconductor device according to the present invention comprises a first transistor and a second transistor, and functions as an inverter. The first transistor includes an island semiconductor layer, a first gate insulating film surrounding the periphery of the island semiconductor layer, a gate electrode surrounding the periphery of the first gate insulating film, p+-type semiconductor layers formed in the upper and lower part of the island semiconductor layer, respectively. The second transistor includes the gate electrode, a second gate insulating film surrounding a part of the periphery of the gate electrode, an arcuate semiconductor layer contacting a part of the periphery of the second gate insulating film, n+-type semiconductor layers formed in the upper and lower part of the arcuate semiconductor layer, respectively. A first contact electrically connects the p+-type semiconductor layer in the first transistor and the n+-type semiconductor layer in the second transistor.