Electron spin resonance (ESR) measurements were performed on conducting Langmuir-Blodgett (LB) films constructed from bis-ethylenedioxy-tetrathiafulvalene (BO) and behenic acid (BA). The temperature dependence of the spin susceptibility and the lint width showed a metallic behavior of conduction electron on the BO network, which is consistent with the negative temperature-derivative of DC conductivity observed previously. The orientation of BO molecule in the films is estimated from the anisotropy of the g-value.