TGG crystal can be used to fabricate various magneto-optical devices, due to its optimum Faraday Effect. In this work, 400-keV He+ ions with a fluence of 6.0 × 1016 ions/cm2 were irradiated into the TGG crystal for the planar waveguide formation. The precise diamond blade dicing with the rotation speed of 20,000 rpm and the cutting velocity of 0.1 mm/s was performed on the He+-implanted TGG planar waveguide for the ridge structure. The dark-mode spectrum of the He+-implanted TGG planar waveguide was measured by the prism-coupling method, obtaining the relationship between the reflected light intensity and the effective refractive index. The refractive index profile of the planar waveguide was reconstructed by the reflectivity calculation method. The near-field light intensity distributions of the planar and ridge waveguides were recorded by the end-face coupling method. The He+-implanted and diamond blade-diced TGG crystal planar and ridge waveguides are promising candidates for integrated magneto-optical devices.