Pure SnO2 nanoparticles with a single tetragonal phase were fabricated and characterized for use as ink solution. It was possible to obtain the SnO2 nanoparticles through the calcination process of SnC204 powders prepared by a hydrothermal reaction of an aqueous solution containing SnCl2 x 2H2O and H2C2O4. The SnO2 powder, synthesized at 600 degrees C, showed a single tetragonal phase, while the powders synthesized at 550 degrees C or lower were composed of a mixture of tetragonal and orthorhombic phases. The particle size of the SnO2 powder with single tetragonal phase was as small as 100 nm and its surface specific area was 12.31 m2/g. It was possible to fabricate the SnO2-nanoparticle-included ink solution for nanoparticle printing by adding a small amount of the previously prepared SnO2 powder to an aqueous solution of glycerol. The region of SnO2 nanoparticles formed by dropping the ink solution was able to successfully fill the gaps between Pt electrodes patterned on SiO2/Si substrates; the range of the gap between the electrodes was from 10 to 100 μm.