The anisotropic properties of the Earth’s velocity structure can be revealed through a combination of receiver function (RF) analysis and shear wave splitting. The splitting parameters, fast polarization direction (FPD) and split time, are used to infer the anisotropic properties. We utilized seismograms from stations on Shikoku Island, Japan, and applied the Bayesian information criterion to constrain the model size of the RF. We showed different anisotropic properties between northern and southern areas corresponding to the Median Tectonic Line. In the southern part, the FPDs were sub-perpendicular to the plunge of the subducting slab, while in the northern part, the FPDs were sub-parallel to the plunge of the slab. Our results indicate that anisotropic strengths are weaker in the tectonic tremor-band in northwestern Shikoku and stronger in the northern part of central and eastern Shikoku around the no-tectonic-tremor area. These anisotropic variations may reveal the geological structure under Shikoku Island.