The macroscopic electronic behavior and atomic arrangements of the GaAs surfaces immersed in HCl solution were studied by surface current transport (SCT), band‐edge photoluminescence (PL), atomic force microscopy (AFM), and x‐ray photoelectron spectroscopy (XPS). SCT measurements indicated reduction of the surface band bending on immersion into HCl solution for bothn‐ andp‐type materials. A remarkable increase of the band‐edge PL intensity was also observed. In the AFM image taken in HCl solution, the (001) surface showed an array of atoms along [110] and [1̄10]direction with the spacing of 4.1 Å, indicating presence of a (1×1) structure. Similarly, (1×1) images with threefold symmetry were observed on the (111)Aand (111)Bsurfaces. The XPS analysis of the GaAs surfaces after immersion into HCl solution detected a monolayer level presence of gallium chloride. These results indicate that bond termination on the GaAs surface by adsorption of Cl atoms to surface Ga atoms realizes a nonstrained regular (1×1) passivation structure which removes surface states from the band‐gap region.