Abstract: A differential apparatus includes a differential casing, a pair of helical side gears and a pair of helical pinion gears. The helical pinion gears are accommodated in bores formed in the differential casing, respectively. The long and short helical pinion gears have respective first gear portions meshing with the side gears, respectively, and second gear portions meshing with each other. Each gear tooth of the long pinion gear is so tapered that tip thickness of the gear tooth is gradually decreased from an axial end of the gear portion toward the other gear portion. Even if the long pinion gear is inclined by meshing reactive forces, it is possible to ensure sufficient tooth bearing areas at respective tooth faces of the pinion gears.