The toe abutment member comprises a jaw unit pivotally mounted on the ski and consisting of two lateral arms adapted to cooperate with the front portion of the ski boot in order to maintain the boot in the axis of the ski, and a resilient device housed within the body of the abutment member for locking the arms in the boot-retaining position with a predetermined stiffness of release. The toe abutment member essentially comprises in addition a feeler member placed in contact with the front portion of the ski boot and adapted to cooperate with the resilient device to reduce the stiffness of release at the time of a forward-fall position and/or when an axial thrust is exerted on the ski boot. The jaw unit is mounted on the body for pivotal displacement about a transverse horizontal axis, and the feeler member is also mounted for rotation about a transverse horizontal axis so as to produce action on the resilient device by reducing its stiffness of release in the further event of a backward-fall position of the skier.