An inlay sole for shoes is made up of sole pieces of varying Shore hardness which engage with each other on abutting edges, the width of which corresponds to the thickness of the sole pieces, with matching sinuous projections and matching recesses. The projections form extensions which engage in backcuts in the recesses, the inlay sole being made of several layers of sole pieces assembled as above. The abutting edges are offset with relation to each other from layer to layer.