A 1D metallic surface state was created on an anisotropic InSb(001) surface covered with Bi. Angle-resolved photoelectron spectroscopy (ARPES) showed a 1D Fermi contour with almost no 2D distortion. Close to the Fermi level ($E_{rm F}$), the angle-in
tegrated photoelectron spectra showed power-law scaling with the binding energy and temperature. The ARPES plot above $E_{rm F}$ obtained thanks to thermally broadened Fermi edge at room temperature showed a 1D state with continuous metallic dispersion across $E_{rm F}$ and power-law intensity suppression around $E_{rm F}$. These results strongly suggest a Tomonaga-Luttinger liquid on the Bi/InSb(001) surface.
