A new high‐stability scanning tunneling microscope (STM) has been developed. Its key design feature is the application of two, concentrically aligned, piezoelectric ceramic tubes, allowingx–y–zmotion of the tungsten tip as well as sample mounting to be cast into a single compact unit. The construction is small, very rigid, and temperature compensated, yielding reduced sensitivity to mechanical and acoustic vibrations and temperature variations. Other advantages of this ‘‘thimble‐size’’ STM include easy sample mounting and, at a later stage, operation under UHV conditions with access to other surface‐analysis (UHV) tools. At present, the microscope is operated in air, and its performance is tested by imaging a highly oriented pyrolytic graphite surface and a Si(111) surface on which a 100‐A˚‐thick Au layer has been deposited.