A fastening member which can fix with sufficient strength siding boards whose lateral joint portions are disposed in a portion where no vertical member is provided and prevent displacement in the vertical direction, is capable of ensuring a ventilation space without using furring strips and has excellent durability, and an external wall construction structure using the same are provided. The pH of the mixed acid is adjusted by adding barium hydroxide as a neutralizer. Each set of the ordnance devices has at least one ordnance device and further includes an ordnance device interface, which preferably includes an optical-to-electrical converter. The connecting device includes a first connection layer and a second connection layer. The radial anisotropic sintered magnet has excellent magnet characteristics without occurrence of cracks in the steps of sintering and cooling for aging, even if the magnet has a shape of a small ratio between an inner diameter and an outer diameter.