PURPOSE: To prevent the variation of threshold voltage, and to accelerate working speed by connecting a body of the SOS type MOS transistor to a power supply.

CONSTITUTION: N Type silicon formed onto an insulator substrate made of sapphire, etc. is removed through etching by using a mask 51, the island of a silicon crystal is shaped, ions are injected by employing a mask 52 and an N type is changed into a P type. The silicon of a gate section is oxidized, and a polysilicon layer is formed in the shape of a mask 53 and used as a gate electrode. N Type impurity ions are shot to a section surrounded by a mask 54, P type impurity ions are shot to regions except the section surrounded by the mask 54, and NMOS drain and source and PMOS drain and source are shaped. In this case, silicon regions 57, 58 extending from silicon regions 5, 6 under the gate electrode are each turned into an N+ type and a P+ type, and can be connected to source lines VSS, VDD.