A heel unit for an alpine touring binding, comprising a binding body which is suitable for holding a heel portion of an alpine touring shoe in a downhill position of the heel unit and for releasing the heel portion of the alpine touring shoe in an alpine touring position of the heel unit, such that the alpine touring shoe can lift off the heel unit, and a climbing aid which is adjustable between an active position and a passive position, wherein, while in the active position, the climbing aid supports the heel portion of the alpine touring shoe at a predetermined height above a sliding board plane in the alpine touring position of the heel unit, wherein the climbing aid is biased over the entire path of movement thereof into the active position by means of a flexible element and can be locked in the passive position.