Abstract: A device attachable to the leg of a ladder to lengthen a leg that is too short to reach the uneven level of a supporting surface comprising a sleeve member clamped below the last and next-to-last rung of the ladder; an extension vertically adjustable in the sleeve; a threaded rod having a stop at its lower end abutting the top of the extension and a handle at its upper end for vertically displacing the extension; the lower end of the extension having pivoted thereon a plate with a skid-proof bottom.