Electron spin resonance spectra of the Langmuir-Blodgett films of 5-, 10-, and 16-doxylstearic acids (DXSTAs) and their mixtures with stearic acid complexed with polyallylamine, polyvinylmethylpyridinium iodide, and polyvinylbenzyltrimethylammonium chloride are measured at various angles between the magnetic field and the film normal. From the difference in the strength of Heisenberg spin exchange interaction among these three kinds of DXSTA films, it was indicated that the mobility of the methylene chain in these films increased with the distance from the head group. From the anisotropic properties of these spectra, it was also shown that the DXSTA molecules were well oriented with their methylene chain almost perpendicular to the film surface and were well arranged two dimensionally in the film lane.