On the upper surface of the ski, where the heel of the ski boot is located, is arranged a sole-plate, perpendicular to the ski axis, which forms part of the safety binding and cannot break loose from it. This plate comprises, at its front head, a front cheek (3) and, at its rear end, an automatic heel-holder (5) operating against a spring so that a front force exceeding the spring strength would lead to the releasing of the ski boot. In order that, whenever an excessive rotating force is applied, the ski boot may be totally released from the sole-plate (2) and consequently from the ski and that, after the releasing of the ski boot, the sole-plate returns to its normal position, the latter comprises, where the big toe and the ski boot heel are located, a slide (15, 16, 17, 18) guiding its displacement while the automatic heel holder (5) has a second degree of freedom. Consequently the release of the ski boot takes place once the strength of a separate spring (36) is exceeded.