PURPOSE: To improve stability by forming a block in the shape of a right-angled triangle placed directly on a foundation on which a concrete wall body is built or through other block and forming a curved recessed part throughout a range of from a top part to a front end part.

CONSTITUTION: A block 1 in the shape of a right-angled triangle is formed with a bottom part 3 fronting on a foundation 2, a back part 5 fronting on the side of a concrete wall body 4 built on a foundation 2, and a curved recessed part 6. Concrete blocks 7 are laminated together on the foundation 2 to build a concrete wall body 4, and the blocks 1 are arranged on the both sides thereof. A roofing tile ground block 9 is placed on the top of the concrete wall body 4, and roofing with tiles 10 thereon is effected to apply a plastering 11. This constitution provides a profound feeling for a plastered wall 8.