Ski boot for ski mountaineering, comprising: a couple of front pins, provided in the front portion of the ski boot at opposed side walls, apt to engage corresponding holes of a toe for ski mountaineering; a couple of front seats, provided in the front portion of the ski boot, each one for receiving one of the front pins; each front pin being movable in the corresponding seat to assume: a climbing configuration, in which it projects from the corresponding seat to engage in not removable manner a hole of a toe for ski mountaineering and to allow the ski boot to oscillate with respect to the axis of the same front pin. a downhill configuration, in which it projects from the corresponding seat to engage removably a hole of a toe for ski mountaineering; a disengaging configuration in which it is in the corresponding seat so that it is disengaged from said hole of the toe; the ski boot being characterized in that it comprises: control means; first connection means (5, 50) housed at least partially in the ski boot and connected to the front pins and to the control means; the control means being constrained to the first connection means (5, 50) so that they can assume: an operating position, in which they act on the first connection means (5, 50) so that the front pins are moved in the respective climbing configuration; an intermediate position in which they act on the first connection means (5, 50) so that the front pins are moved in the respective downhill configuration; and a not operating position in which they act on the first connection means (5, 50) so that the front pins are moved in the respective disengaging configuration; the first connection means (5, 50) being shaped so that, when the front pins are in the downhill configuration and the ski is subjected to a stress higher than a critical one, the front pins are disengaged from the respective hole of the toe, thus allowing the ski boot to be disengaged from the toe. a couple of front pins, provided in the front portion of the ski boot at opposed side walls, apt to engage corresponding holes of a toe for ski mountaineering; a couple of front seats, provided in the front portion of the ski boot, each one for receiving one of the front pins; each front pin being movable in the corresponding seat to assume: a climbing configuration, in which it projects from the corresponding seat to engage in not removable manner a hole of a toe for ski mountaineering and to allow the ski boot to oscillate with respect to the axis of the same front pin. a downhill configuration, in which it projects from the corresponding seat to engage removably a hole of a toe for ski mountaineering; a disengaging configuration in which it is in the corresponding seat so that it is disengaged from said hole of the toe; the ski boot being characterized in that it comprises: control means; first connection means (5, 50) housed at least partially in the ski boot and connected to the front pins and to the control means; the control means being constrained to the first connection means (5, 50) so that they can assume: an operating position, in which they act on the first connection means (5, 50) so that the front pins are moved in the respective climbing configuration; an intermediate position in which they act on the first connection means (5, 50) so that the front pins are moved in the respective downhill configuration; and a not operating position in which they act on the first connection means (5, 50) so that the front pins are moved in the respective disengaging configuration; the first connection means (5, 50) being shaped so that, when the front pins are in the downhill configuration and the ski is subjected to a stress higher than a critical one, the front pins are disengaged from the respective hole of the toe, thus allowing the ski boot to be disengaged from the toe. control means; first connection means (5, 50) housed at least partially in the ski boot and connected to the front pins and to the control means; the control means being constrained to the first connection means (5, 50) so that they can assume: an operating position, in which they act on the first connection means (5, 50) so that the front pins are moved in the respective climbing configuration; an intermediate position in which they act on the first connection means (5, 50) so that the front pins are moved in the respective downhill configuration; and a not operating position in which they act on the first connection means (5, 50) so that the front pins are moved in the respective disengaging configuration; the first connection means (5, 50) being shaped so that, when the front pins are in the downhill configuration and the ski is subjected to a stress higher than a critical one, the front pins are disengaged from the respective hole of the toe, thus allowing the ski boot to be disengaged from the toe.