Disclosed is a brazing structure that includes a ceramic member, a metal layer, a tubular metal fitting and first and second brazing members. The ceramic member includes a small diameter portion and a large diameter portion. The metal layer is located on an outer surface of the large diameter portion. At least an edge of the ceramic member is inserted in the fitting. The first brazing member connects the inner surface of the fitting to the metal layer. The second brazing member does not contact with the metal layer, and fills between at least a part of the small diameter portion and the inner surface, which faces to the part of the small diameter portion, of the fitting. The small diameter portion is located closer to the edge than the metal layer and is inside the fitting.