A rear portion of a ski mountaineering binding, wherein: it comprises a base in order to be fixed to a ski; it comprises a turret which is borne by the base and which is rotatable with respect to the base in order to assume a first position of the turret, wherein it is hookable to the heel of a ski boot, so that it is easy to ski downhill, and in order to assume a second position of the turret, wherein it is not hookable to the heel of a ski boot, so that it is easy to walk uphill; it comprises a brake for a ski which is fixable to the ski and which is able to assume a braking configuration, in which it brakes the ski, and a non-active configuration wherein the brake is non-active; it comprises first elastic means which are arranged to exert a force which tends to bring the brake into the braking configuration; it comprises a hooking member which: is borne by the base; it comprises a hook for hooking the brake; it is movable along a first movement path which is transversal to the axis of the ski, when the base is fixed to the ski; and is activatable to assume a disengaged configuration, wherein the hook is not able to hook the brake, and to assume an engaged configuration, wherein the hook is able to hook the brake when the brake is brought into the non-active configuration, maintaining the brake stably in the non-active configuration; it comprises second elastic means acting on the hooking member, in order to exert a force which tends to push the hooking member into the engaged configuration; it comprises a cam which is borne by the turret and which is arranged in order to assume a first position of the cam, when the turret is in the first position of the turret, and in order to assume a second position of the cam, when the turret is in the second position of the turret; it comprises a pusher which is borne by the base, which is movable along a second movement path and which is activatable by the cam in order to assume a first position of the pusher, when the cam is in the first position of the cam, and in order to assume a second position of the pusher, when the cam is in the second position of the cam; the hooking member comprises an abutment for abutting the pusher, and is activatable by the turret, via the cam and the pusher, to assume the disengaged configuration when the turret is in the first position of the turret and to assume the engaged configuration when the turret is in the second position of the turret. it comprises a base in order to be fixed to a ski; it comprises a turret which is borne by the base and which is rotatable with respect to the base in order to assume a first position of the turret, wherein it is hookable to the heel of a ski boot, so that it is easy to ski downhill, and in order to assume a second position of the turret, wherein it is not hookable to the heel of a ski boot, so that it is easy to walk uphill; it comprises a brake for a ski which is fixable to the ski and which is able to assume a braking configuration, in which it brakes the ski, and a non-active configuration wherein the brake is non-active; it comprises first elastic means which are arranged to exert a force which tends to bring the brake into the braking configuration; it comprises a hooking member which: is borne by the base; it comprises a hook for hooking the brake; it is movable along a first movement path which is transversal to the axis of the ski, when the base is fixed to the ski; and is activatable to assume a disengaged configuration, wherein the hook is not able to hook the brake, and to assume an engaged configuration, wherein the hook is able to hook the brake when the brake is brought into the non-active configuration, maintaining the brake stably in the non-active configuration; it comprises second elastic means acting on the hooking member, in order to exert a force which tends to push the hooking member into the engaged configuration; it comprises a cam which is borne by the turret and which is arranged in order to assume a first position of the cam, when the turret is in the first position of the turret, and in order to assume a second position of the cam, when the turret is in the second position of the turret; it comprises a pusher which is borne by the base, which is movable along a second movement path and which is activatable by the cam in order to assume a first position of the pusher, when the cam is in the first position of the cam, and in order to assume a second position of the pusher, when the cam is in the second position of the cam; the hooking member comprises an abutment for abutting the pusher, and is activatable by the turret, via the cam and the pusher, to assume the disengaged configuration when the turret is in the first position of the turret and to assume the engaged configuration when the turret is in the second position of the turret.