We have developed an extreme high vacuum (XHV) system using a new combination pump cpmposed of a suitably shaped NEG(Non-Evaporable Getters) in the body of a sputter-ion pump (SIP). The stainless-steel test chamber was used which had been well oxidized at $450^{circ}C$ and already yielded XHV with a turbomolecular pumping system. The pressure was measured by a Leybold extractor gauge (EXG,limit:1~$2{ imes}10^{-12}$torr, but in the ultimate pressure regionthe EXG shows an unusual sign as $-0.{ imes}10^{-12}$ torr which indicates much lower pressure range than its available lower limit. These results are mainly due to the high pumping speed of NEG for hydrogen. Furthermore, use of the SIP combined with the NEG as a XHV pumping system implies the potential for actualization of the surface analysis under XHV environment, and allows one to have a chance tp meet a new world in nanometer science and technology.