Ski boot comprising a rigid shell which is shaped so as to accommodate the foot of the user, and has a lower part structured to couple with a ski binding device; a rigid cuff which is shaped so as to surround the lower part of the leg of the user, and is pivotally jointed to the shell thus to be able to pivot about a rotation axis substantially perpendicular to the midplane of the boot, and shell closing means adapted to selectively tighten the shell on the foot of the user; the shell comprising a substantially basin-shaped casing which is superiorly provided with a main opening from which the leg of the user comes out, and with a longitudinal slit that branches from said main opening and extends along the casing towards the front tip of the shell; the shell closing means being placed at the longitudinal fissure.