This paper describes the fabrication of tungsten tips with high aspect ratios for use as probes in scanning tunneling microscopy. A Teflon bath with the hydrophobic property is employed as an etching bath instead of the use of conventional glass beakers. Hydrophobicity of the Teflon bath with a unique shape causes a gradual decrease of the meniscus during the etching process. Owing to this effect, tungsten tips with high aspect ratios and resonance frequencies can be easily fabricated without the help of any additional mechanical and electrical parts. The fabrication of W tips with radii of curvature down to 20 nm is demonstrated using the new method. The reproducibility of the unique W-tip structure is also experimentally confirmed.