To beautifully finish cracking processing on a wall balustrade by securely inducing cracking at a joint part at low cost.

When a wall balustrade 10 is constructed by casting concrete into a formwork 2, cracking induction joints 12, 13 are constructed by casting concrete while a plate 4 for slit formation is protruded from projections 3 for shrinkage joint formation provided to a formwork 2. Specifically, the plate 4 for slit formation is sandwiched between chamfer strips 2 forming the projections 3 for shrinkage joint formation. Then the projections 3 for shrinkage joint formation and the plate 4 for slit formation are formed up to a haunch part 11 of the wall balustrade 10. Further, an acrylic plate is used as the plate 4 for slit formation.