Abstract: An adjustable support structure for an operating equipment that is adjustable in a plurality of directions so as to enable level mounting of the equipment with respect to the horizontal plane on a roof surface, for instance. The adjustable support structure includes a base member, a support member capable of accepting and supporting a desired piece of equipment, and means for adjustably coupling the support member to the base member including adjusting the position of the support member in a plurality of directions and maintaining the support member in a desired position with respect to the base member. The support structure can be used on a plurality of surfaces that are either relatively flat and level with respect to the horizontal plane or are inclined.