To achieve stable construction work and operational safety by mounting projecting hardware for an exterior wall, heat insulators, and exterior wall members to an exterior wall in a factory in advance; provide great strength combined with a smaller cross-sectional area by means of the cross-sectional shape of the hardware causing the exterior wall members to project; enable use of heavy exterior wall members; and secure appropriate ventilation through a ventilating layer even if there is a wide window with a wide opening.

Equally spaced, grooved vertical furring strips 2 which should be kept parallel to a precast concrete panel 3 have an appropriate number of grooved insert brackets 1 attached thereto, the brackets being vertically inserted into the wall surface part 3A of the precast concrete panel in such a manner as to correspond to the vertical furring strips 2. A heat insulator 4 is inserted between the wall surface part 3A of the precast concrete panel and the vertical furring strips 2 and a thread 1A on the end of each insert bracket is passed through each vertical furring strip 2 and tightened by an end nut 6, whereby the exterior wall member 5 is attached to the vertical furring strips 2.