A height adjusting structure is adapted to support objects and adjust height of the objects, including a supporting body having at least one receiving portion, and at least one side of the receiving portion having a sliding groove with height difference; a shaft tube disposed in the receiving portion and having spiral trails on a surface thereof; a sliding base disposed in the receiving portion and sleeved on the shaft tube, a spiral connecting portion formed in an inner edge of the sliding base and corresponded to the spiral trails; and a torque unit sleeved on the shaft tube and two ends of the torque unit are separately fixed in the axis block and the shaft tube. Whereby the sliding base supports objects and the sliding base is slid along the sliding groove in the receiving portion to adjust height of the objects.