PURPOSE:To compensate a non-linear characteristic of LED without adjustment and automatically and to make a low skew analog light transfer low-priced and mass produce by installing, at the receiving side, a skewness detecting circuit to detect a skew component of the transfer signal and a skewness compensating circuit to operate so that the skew component can be minimum in accordance with the detecting quantity of the skewness detecting circuit. CONSTITUTION:A light input signal inputted from an input signal 1 passes through a LED driving circuit 3 and drives LED4 as it does. The light output signal of LED4 is transferred by a light transmission line, and converted to an electric signal by a photo-detecting element 6. The electric signal is amplified by a receiving amplifier 7 and inputted to a skewness compensating circuit 12. In the electric signal inputted to the skewness compensating circuit 12, the skew component is detected by a skewness detecting circuit 13. The skewness compensating circuit 12, based upon the skewness quantity detected by the skewness detecting circuit13, automatically adjusts so that the skew part detected by the skewness detecting circuit 13 may be minimum. Thus, by compensating the non-linear characteristic of LED without adjustment and automati cally, the low skewness analog light transfer can be mass-produced low-pricedly.