A differential device includes pinion; pinion shaft; paired side gears connected to paired output shafts and having at outer peripheral portions gear portions meshing with the pinion; and oil introduction passage introducing lubricant oil to mutually-facing surfaces of the side gears. An oil reserving portion facing space adjacent to end surface of the pinion on radially inner side and capable of catching and holding lubricant oil splashed to the space is formed in portion where the pinion and the pinion shaft mutually face, so as to communicate with fitting portion between the pinion and the pinion shaft where they are relatively rotationally slidable. A step portion is formed in at least one of the mutually-facing surfaces, separates part of oil from lubricant flow flowing radially outward along the one surface by centrifugal force, and guides the oil into the space.