An object of the present invention is that the capacitance of MOS capacitors is changed without varying the kind of an impurity (a donor or an acceptor) in a channel formation region, and an n-type MOS capacitor and a p-type MOS capacitor are formed over a same substrate. By changing the offset length between a contact region and a channel formation region, the capacitance of a MOS capacitor can be changed without increasing the number of manufacturing process. Also, an n-type MOS capacitor and a p-type MOS capacitor can be formed over a same substrate only by changing the offset length. In addition, an n-type MOS capacitor and a p-type MOS capacitor can be formed over a same substrate by changing the dose amount of impurity with respect to a channel formation region while fixing the offset length.