The invention concerns a ski boot/ski binding combination with an adapter for various sizes of ski boots consisting of a plate-like part and an underside attachment member. The ski boot is removably fastened on to the plate-like part of the adapter. The attachment member serves as the mounting support for the adapter on the ski by means of spring-loaded ski binding parts.The attachment spans in the longitudinal direction of the adapter plate over a length corresponding to the metatarsus and the front tarsus area of the skier's foot in the ski boot. This provides the skier with support in the major stretching part of his foot when walking with the adapter.