The phase transition behavior and the electro-rheological (ER) effect for a neat sample of the side chain type liquid crystalline polysiloxane were investigated in the vicinity of the isotropic-liquid crystalline phase transition temperature. The dependence of the dynamic viscoelastic properties upon temperature under no electric field changed at 308.1 K which was consistent with the isotropic-liquid crystalline phase transition temperature measured by the polarized optical microscopy. The shear thinning was observed under steady shear flow and no electric field at temperatures of 305 K as well as 313 K. The ER effect was also observed at the same temperatures and the shear rates at which the shear thinning was observed. It was thought that the ER effect is closely related to the shear-induced alignment of anisotropic domains as well as mesogenic side groups under high shear fields before application of external electric fields.