A base, supported on a platform, has a plate pivotably coupled therein, and side walls of the base are apertured to receive rods. The rods maintain the plate in a selected inclination, as they are fitted through the apertures and hold the plate in position. The plate receives one upright of a ladder, in order to make the upright level with the other upright of the ladder on pitched ground, or uneven bearing surfaces, in which the two uprights cannot otherwise bear on a common-level surface.