A micromechanical component is described including a substrate having a spacer layer and a test structure for ascertaining the thickness of the spacer layer. The test structure includes a seismic mass, which is elastically deflectable along a measuring axis parallel to the substrate, a first electrode system and a second electrode system for deflecting the seismic mass along the measuring axis, having a mass electrode, which is produced by a part of the seismic mass, and a substrate electrode, which is situated on the substrate in each case, the first electrode system being designed to be thicker than the second electrode system by the layer thickness of the spacer layer.