The semiconductor device of the present invention is a semiconductor device including P-type and N-type thin film transistors, at least one of the N-type thin film transistors having an off-set gate structure, at least one of the P-type thin film transistors having a LDD structure, wherein a P-type high concentration impurity layer for forming the at least one P-type thin film transistor is formed on the semiconductor layer in a region other than a region below a gate electrode and a sidewall spacer and contains a higher concentration of a P-type impurity together with an impurity contained in an N-type low concentration impurity layer and an N-type high concentration impurity layer for forming the N type thin film transistor.