To provide a semiconductor device having excellent productivity and a manufacturing method of the same.

A semiconductor device 100 comprises: a silicon substrate 101; and an N-type transistor 200 and a P-type transistor 202 provided on the same silicon substrate 101. The N-type transistor 200 and the P-type transistor 202 each includes a high dielectric constant gate insulator 108 containing Hf and a TiN film 110 provided on the high dielectric constant gate insulator 108. The N-type transistor 200 includes an La-added SiO₂ film 109a between the silicon substrate 101 and the high dielectric constant gate insulator 108. The P-type transistor 202 includes an La-added SiO₂ film 109b containing a chemical element for work function adjustment same as that contained in the N-type transistor 200 between the high dielectric constant gate insulator 108 and the TiN film 110.