Abstract: A differential gear mechanism in which when a plurality of contact lines between a gear tooth and a pinion tooth is defined on either a tooth surface of the gear tooth of a crown gear or a tooth surface of the pinion tooth of a pinion gear at a predetermined angle around an axis of the pinion gear, and the plurality of contact lines and a center line of a pinion tooth bottom surface of the pinion gear are projected onto a plane, including an axis of a pair of the crown gears, around the axis of the pinion gear, the center line of the pinion tooth bottom surface projected onto the plane includes an inclined line passing through a range between two of the contact lines which are selected from the plurality of contact lines projected onto the plane and by which a contact ratio is 1.0 or higher.