In an electric potential generating device, a source of an N type MIS transistor is mutually connected to that of a P type MIS transistor and also connected to an output terminal. A drain of an N type MIS transistor 54 is connected to a power supply voltage supply portion for supplying power supply voltage VDD, and a drain of the P type MIS transistor is connected to a ground. In addition, a substrate potential of the N type MIS transistor is a ground voltage VSS, and that of a P type MIS transistor 56 is the power supply voltage VDD. Thus, it is constituted as a source follower circuit for taking output out of the source. It is possible, by utilizing this electric potential generating device, to obtain a logic transformation circuit for stably switching between NOR operation and NAND operation.