There is provided a power semiconductor device, including a plurality of trench gates formed to be spaced apart from each other by a predetermined distance, a current increasing part formed between the trench gates and including a first conductivity-type emitter layer and a gate oxide formed on a surface of the trench gate, and an immunity improving part formed between the trench gates and including a second conductivity-type body layer, a preventing film formed on the surface of the trench gate, and a gate oxide having a thickness less than that the gate oxide of the current increasing part.