A final reduction gear device including an orthogonal axis gear and a speed reduction mechanism portion employing a planetary gear is provided. A radial bearing, more specifically a cylindrical roller bearing, having a large radial load capacity is disposed between a bevel ring gear of the orthogonal axis gear and a differential case. A thrust bearing, more specifically a thrust ball bearing or a thrust roller bearing, having a large axial load capacity is disposed between an axial end portion of a sun gear, and an inner race side of the radial bearing and the side of a fitting portion of the differential case, to which the inner race is fitted. A thrust bearing, more specifically a thrust ball bearing or a thrust roller bearing, having a large axial load capacity is disposed between the bevel ring gear and a planetary carrier of the speed reduction mechanism portion.