Abstract: Alpine ski boot comprising a shell base (1), inside which a device for tightening the foot of the skier is installed. The cam of the operating lever comprises sequential, connected first, second, and third surfaces (13a, 13b, 13c), the first surface (13a) extending at a relatively short distance (a) from the hinge pin (14), the second surface (13b) extending substantially horizontally in the unlocked position and being positioned at a distance (b) from the hinge pin (14) and beneath the latter, this distance being greater than the distance (a) separating this pin and the first surface (13a); and the third surface (13c) of the cam of the operating lever being positioned at the same distance (b) from the hinge pin (14) as the second surface (13b).