To simply and steadily support the upper end of an external wall panel on a lower flange in the case where a floor material is provided on the upper flange of a beam.

A support metal fitting 10 is attached to the lower flange 13 of a beam 11. The upper end of a support bolt 25 protruding upward from a external wall panel 1 is inserted through the bolt hole 23 of a support plate 21 of a support metal fitting 10 protruding to the outside of the beam 11 below the lower flange 13, and a nut 27 threadedly engaged at the upper end of the support bolt 25 keeps the support bolt 25 so as not to drop for suspendingly supporting the upper end part of the external wall panel 1.