A semiconductor device including a p-type SiC layer, a gate electrode, and a gate insulating layer therebetween, the gate insulating layer including a first layer, a second layer provided between the first layer and the gate electrode and having a higher oxygen density than the first layer, a first and second regions provided in the second layer, the first region including a first element (at least one of Ta, Nb and V) having a first concentration peak, and the second region including a second element (at least one of Ge, B, Al, Ga, In, Be, Mg, Ca, Sr, Ba , La, and lanthanoid) having a second concentration peak of the second element and a third concentration peak of C, a distance between the second concentration peak and the third concentration peak being shorter than a distance between the first concentration peak and the third concentration peak.