To reduce the excavation width and excavation area of a ground surface on the rear side of a retaining wall by using retaining wall blocks consisting of vertical wall slabs and horizontal bottom slabs continuously connected on the front sides of the vertical wall slabs.

A ground surface, on which a retaining wall is installed, is excavated and foundation crushed stones 3 are spread and levelled, and foundation concrete 2 is placed on the top faces of the crushed stones 3. Bed mortar 7 is spread and levelled on the top face of foundation concrete 2 and a retaining wall block 6 is mounted, and excavated soil is filled back on the rear side of a vertical wall slab 4 and the top face side of a horizontal bottom slab 5. Pavement 12 for a footway is executed on the top face of a back-filled soil layer in the upper section of the horizontal bottom slab 5, and a side ditch 13 is set up to a section near to the vertical wall slab 4 of the pavement 13 for the footway. Joint bars 8 are fitted into the bank section 1 of foundation concrete 2 for reinforcement, sealing concrete 9 is placed horizontally on the rear side of the vertical wall slab 4, and back-filling crushed stones 10 are piled up to the upper section of sealing concrete 9. Rag-stone patterns, etc., are decorated on the front of the vertical wall slab 4, and the retaining wall is harmonized with peripheral environment.