We have constructed a new scanning tunneling microscope (STM) that usesxandzinchworms for micropositioning in an ultrahigh vacuum environment. One (zinchworm) is for approaching the tip to the sample surface and the other (xinchworm) is for both cleaving the sample and moving the sample to positions of interest. We have demonstrated that this STM is very useful for observing the cross section of a thin epitaxial layer, such as the cleaved (110) surface of a Ga0.47In0.53As/InP multiquantum well (MQW) structure. The STM image of GaInAs well layers and InP barrier layers has been shown to reflect the feature of the MQW potential. Moreover, we have obtained images of the filled states on the group‐V anions in the GaInAs and InP layers.