Disclosed herein is a semiconductor device having a vertical MOS transistor having a channel of a first conductivity type and formed by burying a gate electrode in a semiconductor substrate, a planar MOS transistor having a channel of the first conductivity and having a gate electrode formed on the semiconductor substrate, and a planar MOS transistor having a channel of a second conductivity and having a gate electrode formed on the semiconductor substrate, the semiconductor device, including other circuit element(s), other than a transistor, formed either below or above the vertical MOS transistor having the channel of the first conductivity type.