PURPOSE: To simply carry out positioning and execution in a short time, and to secure waterleakage resistance and strength after the execution by engaging an engaging piece in the engaging piece receiver of a longitudinally spreading building exterior wall member fixed to the furring strips of a building.

CONSTITUTION: In metal plates which are fixed in order to the side of the furring strips 7 of a building to form an exterior wall, an engaging piece receiver 3 is formed on the side edge on one side of a wall face body 2, and an adjoining engaging piece 4 is formed on a side edge on the other side. In this case, the side of the engaging piece receiver 3 is provided with a groove-shaped recess 3b having an opened opening part 3c, and the opening part 3c is provided with a projection 3d corresponding to the recess 3b. In addition, a bottom flat plate 3e abutting on the furring strips 7 is formed, and a supporting flat plate 4bb whose fitting in part 4b abuts on the bottom flat plate 3e and a groove-shaped recess bottom 3ba is formed. A locking part 4ba locks in the projection 3d of the engaging piece receiver 3 at the end edge portion of the metal plate, and moreover the engaging piece receiver 3 of the adjacent longitudinally spreading building exterior wall material 1 is engaged with an engaging piece 4. Thus a desired space 5 which is noncommunicated with the opening 3c is formed between the engaging pieces 3, 4.