A semiconductor device is provided comprising several device components formed in the same substrate, such as a P-substrate having an offset Nch transistor including N-type source and drain each formed in a P-well spatially separated from one another, and the drain surrounded by a low concentration N-type diffusion layer; an offset Pch transistor including P-type source and drain each formed in an N-well spatially separated from one another, and the drain surrounded by a low concentration P-type diffusion layer; a triple well including a deep N-well, and a P-type IP well formed therein; a normal N-well for forming a Pch MOS transistor; and a normal P-well for forming an Nch MOS transistor; in which simultaneously formed are the low concentration N-type diffusion layer, N-well and normal N-well; the P-well and normal P-well; and the low concentration P-type diffusion layer and IP well.