To secure a flow rate of linear flow of combustion air toward the extending direction of a burner gun.

This combustion device comprises the burner gun 2 mounted toward the prescribed direction, first supply means 4, 5, D supplying the combustion air X as swirling flow around on the prescribed direction as a central axis, and second supply means 3b, 4 supplying the combustion air X as the linear flow toward the prescribed direction, and the second supply means 3b, 4 have air blowout openings 3b for linear flow combustion surrounding the burner gun 2 around on the prescribed direction as the central axis.