Abstract: The present invention provides a steel frame beam-reinforcing metal fixture that is capable of recovering the full strength of a steel frame beam to a greater extent than a conventional steel frame beam-reinforcing metal fixture for an S structure. A steel frame beam-reinforcing metal fixture is substantially fitted to a web opening in an SRC beam. An outer peripheral portion of the steel frame beam-reinforcing metal fixture is fillet-welded to a steel frame beam web. The axial length of the steel frame beam-reinforcing metal fixture is between 0.5 and 200.0 times the thickness thereof in the radial direction. Furthermore, in the steel frame beam-reinforcing metal fixture, a length from one end side of the steel frame beam web to one end of the outer peripheral portion and a length from the other end side of the steel frame beam web to the other end of the outer peripheral portion are each at least 0.7 times the thickness of the steel frame beam web.