Nano-scale materials attract interest in fundamental science and technology. Because nano-meter scale materials behave as a new matter, differently from the condenced matter or liquid. As seen from magic number of clusters and carbon nanotubes, nano-scale matter presents degitized and/or quatized characteristics. These characteristics relate with nature of their surface characteristics. We developed an UHV high-resolution electron microscope combined with a miniaturized STM , which enabled us to study nanowires extending our previous analysis on Si(111)7x7 reconstruction. The gold nanowires were found to have multi-tube structure, like carbon nanotubes. In gold tube, each tube consits of gold atomic rows which coil the axis of the tube. The number of atomic rows in the outer tube increases by seven from that of the inner tube, so that the shell closing number is seven. The present STM combined UHV-TEM allow us to open new sciece of the nano-scale matter.