Step-in sole plate ski binding

In a ski binding including a toe release unit, a heel retainer unit, a sole plate adapted to be received between and releasably retained by the units, and securing devices on the sole plate whereby the sole plate may be attached to a ski boot, the improvement including structure at the interface of the sole plate and the heel retainer unit for releasably capturing the sole plate in the heel retainer unit upon the application of force to the sole plate in a direction tending to align the heel retainer unit and the sole plate to allow a skier having the sole plate attached to a ski boot to step into the toe release and heel retainer unit on a ski on which they may be mounted.