The paper presents experimental study of the spin Seebeck effect based on the widely used ferromagnetic Co₇₉Si₁₀X layer, partially covered with Pt layer. The total thickness of tested sample is about 20 μm, which makes it the first confirmed presence of the spin Seebeck effect in bulk material. Experiment was carried out under magnetic flux density 300 mT, room temperature and for constant temperature difference across the sample ranging from 1 K to 21 K. The measured value of induced voltage drop achieved 0.5 μV per 1 K.