A vehicle differential device includes: a differential casing having a pair of axle supporting holes; a pinion gear; a pair of side gears; and a pair of washers each interposed between a contact surface of the differential casing and a back surface of each side gear. The differential casing defines first lubrication grooves provided in an inner circumferential surface of each axle supporting hole, and second lubrication grooves and third lubrication grooves provided in the contact surface. Each second lubrication groove communicates at its end with the corresponding first lubrication groove, and communicates at another end with a space. Each third lubrication groove communicates at its end with the corresponding first lubrication groove, and is closed at another end, without the third lubrication groove being in communication with the space.