Height adjustment mechanism

A height adjustment mechanism disposed in a body is provided, which includes two axle seats disposed on the body, a spindle, two support parts fixed on the spindle, and a stop component. Each of the support parts has a fitting hole, and the spindle is rotatably disposed in the body, and drives the support parts to rotate simultaneously, the spindle has a positioning part having a plurality of grooves, and each of the two support parts has a plurality of asymmetric end surfaces. Any one of the end surfaces is selectively pressed against a plane, such that different height differences exist between the body and the plane. The stop component is corresponding to the positioning part, and is movably disposed in the body, and the stop component moves between a stop position that is clamped in the grooves and a release position where the spindle is allowed to rotate freely.