To provide an asymmetrical transformer for telephone line that prevents a structure of an echo cancellation circuit provided between a transformer and a transmission/reception head from being complicated by increasing a voltage in a transmission direction without decreasing a voltage in a receiving direction.

The asymmetrical transformer is provided between a 2-wire line and a transceiver, has at least one primary winding with 1st number of turns connected to the 2-wire line and at least three secondary windings of series connection connected to the transceiver. The asymmetrical transformer is characterized by that respective number of turns of the secondary windings connected in series depends on a desired transformation ratio for the transmission and reception.