Abstract: A transmission unit with reduced crosstalk signal includes a first conductor group having at least one first conductor surrounded by a first sheath and at least one second conductor surrounded by a second sheath. The first and the second conductor are axially arranged corresponding to one another. The first sheath has a dielectric coefficient higher than that of the second sheath, so that a difference in dielectric property exists between the first and the second conductor to enable reduction of crosstalk occurred during high-speed signal transmission over the transmission unit.