Abstract: A box-like platform having a mast leveling hinge support anchored thereto and a mast structure pivotally attached to the upper end of the hinge support is pivotally attached at one of its ends to an elongated skid unit. The opposite end of the platform is arranged to be raised or lowered by a pair of jacking assemblies connected to the skid unit to effect leveling of the platform. A hydraulic ram having one end connected to the mast and the other end connected to a ram beam supported by a lower extension of the platform enables the mast to be raised to its upright position. By utilizing the ram in conjunction with the leveling characteristic of the platform, the mast assembly can thus be raised to a level and stable condition without the skid unit being perfectly level with respect to the earth's surface. The apparatus permits proper alignment of the mast to the center line of the well to compensate for settlement of the skid unit on an unlevel foundation.