PURPOSE: To improve the fitting structure of an external wall panel, by attaching metal fittings of the external wall panel to fit the edge thereof at every specified distance in the longitudinal direction of a column.

CONSTITUTION: Metal fittings 21 of an external wall panel by which the edge 12a of the corner external wall panel 12 is fixed to a column 2 with a nearly square-shaped section at every specified distance along the longitudinal direction, are welded in advance. Then the edges 11a of the external wall panel 11 are positioned oppositely at the edge 12a with a joint 31 having a certain distance and a frame member 33 with a generally square section is attached vertically to the rear face of the edge 11a. And a frame member 34 with a deformed U-shaped section is attached up and downward to the rear face of the edge 12a. Next, the flange 35 positioned at the joint 31 side of the frame member 34 is fixed to the metal fittings 21 with rivets 36 and a waterproof member 37 is arranged at the external side of the flange 35. In this way, since the panels 11, 12 are directly attached to the column 2, the fitting accuracy is improved.