This cable pair twisting machine (1) is provided with a rotary body (13) which can rotate about both a prescribed rotation axis and a twist axis (8) perpendicular to the rotation axis, a first mechanism (4) which feeds electric cables twisted together by the rotary body downstream, and a second mechanism (5) which can apply a clockwise or counterclockwise twist to each of the two electric cables supplied to the rotary body. The second mechanism is provided with: a first roller unit (17) and a second roller unit (18) which, separated by a prescribed space, sandwich the two electric cables; and a slide mechanism (19) which slides the first roller unit and/or the second roller unit.