Abstract: A safety ski binding uses a rigid sole plate adapted to be releasably secured to a ski boot and having front and rear cam surfaces formed thereon for cooperation with toe and heel pieces that secure the sole plate, and thus the boot, to the ski. The toe piece and heel piece of the ski binding are both mounted on a ski plate or chassis secured to the ski in a predetermined position. The toe includes means defining a movable cam surface which engages the front cam surface of the sole plate, to releasably hold the plate on the ski, while the heel piece includes a resiliently biased cam that engages the rear cam surface of the sole plate when the sole plate is engaged in the toe piece and is flat against the ski, thereby to bias the sole plate towards the toe piece and normally maintain the front cam surface of the sole plate in engagement with the cam surface of the toe piece.