Anisotropic dynamics of benzonitrile (BzCN) confined in the cocrystalline region of syndiotactic polystyrene (sPS) was studied by means of dielectric spectroscopy. Especially examined was the effect of orientation of the crystalline phase for two types of cocrystals, delta and epsilon clathrates, on the dielectric relaxation behavior. The relaxation time of the BzCN in the delta cocrystal, regardless of its orientation, was found to be longer than that in the epsilon cocrystal, indicating that the delta structure has higher degree of constraint on the guest motion than the epsilon structure. With respect to dielectric intensity Delta epsilon due to the guest BzCN relaxation, uniaxial stretching treatment caused different effects in the delta and epsilon cocrystals: Delta epsilon increased for the delta cocrystal and decreased for the epsilon crystal by stretching. This observation was attributable to the difference in directionality of anisotropic motion of the guest molecule inside the cavities of these cocrystals. The preferable orientation of the molecular axis of BzCN corresponding to the vector direction of the dipole moment was perpendicular. to the sPS chain axis (c-axis) for the delta cocrystal, whereas it was parallel to that for the epsilon cocrystal. Since the stretching of the sPS/BzCN film made the c-axis align parallel to the film surface, the normal direction of the rotation plane of BzCN was set perpendicular to the electric field imposed on the sample films (to the thickness direction) for the delta cocrystal and parallel to it for the epsilon cocrystal. Such arrangements of the rotation axis to the electric field resulted in the increase and the decrease in Delta epsilon for the stretched delta and e cocrystals, respectively. The experimental findings indicated the possibility that the dielectric properties of sPS cocrystal films could be changed by controlling the structure and crystallite orientation of sPS cocrystals.