A semiconductor device capable of reducing deterioration of electron mobility while suppressing depletion of gate electrodes is provided. This semiconductor device includes a metal-containing layer so formed that at least either a first gate electrode or a second gate electrode partially covers a corresponding first or second gate insulating film and a semiconductor layer formed on the metal-containing layer to come into contact with a portion of the corresponding first or second gate insulating film not covered with the metal-containing layer. The first and second gate electrodes contain metals different from each other.