A Ag‐Se/Ge‐Se inorganic resist is applied in x‐ray lithography using synchrotron radiation (SR). Usable sensitivity of 0.3–3 times that of a polymethylmethacrylate (PMMA) resist and high contrast (&ggr;∼3.5) are obtained through SR exposures. By utilizing the fringes of masked SR flux caused by Fresnel diffraction, 500‐A˚‐wide fine lines are formed by using x rays of 2–10 A˚ in wavelength. It is determined that a high‐density resist, such as a Ag‐Se/Ge‐Se inorganic resist, is favorable for forming micropatterns using x rays because of the short ranges of the electrons generated by the x rays in the resist.