A cage for a ball bearing is provided with a wire having a first group of heels spaced apart in the circumferential direction and form a first discontinuous ring, a second group of heels spaced apart in the circumferential direction and form a second discontinuous ring, and a plurality of connecting portions extending between one of the heels of the first group and second group. The connecting portions and the heels of the first group and/or the second group delimit a plurality of spaces each intended to receive a ball of the bearing. The cage also provides at least one interposed part disposed inside each space and is provided with a body for accommodating a ball and coupling means for fastening the body to at least one of the connecting portions of the wire. Each of the bodies of the interposed parts fully positioned in the circumferential direction.