The structure changes with the phase transition of liquid crystalline monosubstituted ferrocene derivatives, [4- ω(cholesteryloxycarbonyl)alkoxycarbonyl]phenyl]ferrocene, have been studied using a X-ray PSPC system. The results of the X-ray measurements agreed very closely with those of DSC measurements and polarizing microscopy texture observations. It was suggested that a layer structure existed in a crystal and a liquid crystal phases of the samples. The long spacing values were estimated from the PSPC data. The long spacing value of liquid crystal phase was not so much different from that obtained in our previous work. Consequently, the structure model of the liquid crystal phase previously presented can be applicable to this study. In addition to the liquid crystal structure model, the reasonable models of the crystals will be newly presented in this paper.