A method is adopted for deposition technology using a focused ion beam device, characterized by enabling structures to be formed by using phenanthrene as a source gas and using ions of gallium or gold, silicon or beryllium etc. of energies of 5 to 100 keV from a liquid-metal ion source as ions so as to give a gas blowing density of five to ten times greater than the case of deposition in the related art, with directionality of the gas blowing being both isotropic and symmetrical.