A vehicle differential unit that includes a first gear member rotatably supported by a support member formed of a rotatable member, and a second gear member and a third gear member that mesh with the first gear member, and that distributes a driving force from a drive source of a vehicle to a pair of output shafts via the first gear member, the second gear member, the third gear member, and the support member, characterized in that at least one of the support member, the second gear member and the third gear member is formed of a plurality of separate elements (20A, 21A) that are unable to rotate relative to each other on an axis of the pair of output shafts; the plurality of elements (20A, 21A) include a first element having a first helical spline and a second element having a second helical spline that meshes with the first helical spline, together with the first element, the second element forms a thrust force generation portion (220A, 250A) that receives the driving force and generates a thrust force along an axial direction of the pair of output shafts between the plurality of elements when the first element and the second element relatively move to one side of the axial direction and other side of the axial direction respectively along the axial direction of the pair of output shafts, the vehicle differential unit further has a relative movement limiting portion (251A, 22A) that limits a relative movement between at least two adjacent elements along the axial direction due to the thrust force when the vehicle is in one of a drive mode and a coast mode, at least one of the support member, the second gear member and the third gear member has a first contact face and a second contact face that contact each other when the relative movement between the first element and the second element is limited by the relative movement limiting portion (251A, 22A); and the first contact face is formed in one of the first element and the second element, and the second contact face is formed in the other element. characterized in that at least one of the support member, the second gear member and the third gear member is formed of a plurality of separate elements (20A, 21A) that are unable to rotate relative to each other on an axis of the pair of output shafts; the plurality of elements (20A, 21A) include a first element having a first helical spline and a second element having a second helical spline that meshes with the first helical spline, together with the first element, the second element forms a thrust force generation portion (220A, 250A) that receives the driving force and generates a thrust force along an axial direction of the pair of output shafts between the plurality of elements when the first element and the second element relatively move to one side of the axial direction and other side of the axial direction respectively along the axial direction of the pair of output shafts, the vehicle differential unit further has a relative movement limiting portion (251A, 22A) that limits a relative movement between at least two adjacent elements along the axial direction due to the thrust force when the vehicle is in one of a drive mode and a coast mode, at least one of the support member, the second gear member and the third gear member has a first contact face and a second contact face that contact each other when the relative movement between the first element and the second element is limited by the relative movement limiting portion (251A, 22A); and the first contact face is formed in one of the first element and the second element, and the second contact face is formed in the other element.