To provide execution structure of weathering device for the ends of a building panel and an execution method thereof with a joint section of relatively good appearance between both weathering metal fixtures.

In a pair of weathering metal fixtures 2a and 2b for covering the end edges of a building panel 1, the weathering metal fixtures 2a and 2b having an approximately U-shaped section are constituted of upper plates 3a and 3b, side plates 4a and 4b and lower plates 5a and 5b, and fitting sections 6a and 6b are formed over the longitudinal length on the outside of the side plates 4a and 4b of the weathering metal fixtures 2a and 2b. A joint section 7a connecting one pair of weathering metal fixtures 2a and 2a in the longitudinal direction in not made to coincide with a joint section 7b connecting the other pair of weathering metal fixtures 2b and 2b to fit the fitting section 6a between one pair of weathering metal fixtures 2a to the fitting section 6b between the other pair of weathering metal fixtures 2b, and one pair of weathering metal fixtures 2a are connected to the other pair of weathering metal fixtures 2b to mount both weathering metal fixtures 2a and 2b to a substrate member 8.