A bus bar unit includes a bus bar holder, a U-phase bus bar group, a V-phase bus bar group, and a W-phase bus bar group each including a first layer bus bar located on one side of the bus bar holder in an axial direction and extending along a plane perpendicular to the axial direction, a second layer bus bar located on one side of the first layer bus bar in the axial direction and extending along the plane perpendicular to the axial direction, and an external connection terminal connected to the first layer bus bar and the second layer bus bar and extending from the first layer bus bar and the second layer bus bar toward one side in the axial direction. The first and second layer bus bars of each of the U-phase bus bar group, the V-phase bus bar group, and the W-phase bus bar group extend to opposite sides from each other in a circumferential direction from the external connection terminal connected thereto.