It is possible to surely prevent reflection caused by discontinuity in characteristic impedance on a transmission line or a cable and an increase in a circuit size on the side of a receiving circuit. A data transmitting circuit for transmitting data through the transmission line comprises: a reflection suppressive component generating circuit for generating a reflection suppressive component for suppressing the reflection caused by the discontinuity in the characteristic impedance on the transmission line; and a data output circuit for amplifying the reflection suppressive component and the data to be currently transmitted to the receiving side and outputting them to the transmission line.
