In a combustion apparatus that includes a burner constituted by a burner body, an inside of which an air-fuel mixture is supplied to and one surface of which is made into an open surface, and a combustion plate covering the open surface of the burner body, and a combustion box enclosing a combustion space of the air-fuel mixture ejecting from the combustion plate, an offset part that is positioned at a portion which is away from the swelling part in an inflow direction of the air-fuel mixture to the inner chamber and does not oppose to a tip part(s) of the ignition electrode(s) through the combustion plate is provided with the opposite wall of the burner body and the offset part offsets to a combustion-plate side so that a distance between the offset part and the combustion plate becomes shorter than that between the combustion plate and a general part of the opposite wall except the swelling part and the offset part.