To easily secure an orderly line of the front face of a wall slab and economically construct a sturdy retaining wall which can sufficiently withstand different side pressures of respective upper and lower layers.

A support block 1 having a wider depth as it goes to the lower end, constituted of a single body or the lowermost stage support block 1 constituted of a plurality of vertical stages, is integrally connected onto a foundation concrete layer 3 by vertically tensed PC steel materials 2. When the support block is constituted of a plurality of stages, vertically adjacent support blocks 1 are integrally connected to each other by vertically tensed PC steel materials 2 and wall panel blocks 4 made of a single body or constituted of a plurality of vertical stages are fitted between the right and left support blocks 1 erected at every specified distance in the lateral direction to prevent the blocks from shifting to the front side. And the space surrounded by the wall slab constituted of the support blocks 1 and the wall panel blocks 4, the foundation concrete layer 3 and the excavated slope 5 is filled back with soil 6 or the like.