The transmission system of the present invention is designed to transmit a plurality of signals between the transmitter and the receiver using a plurality of carriers and comprises a radio link characteristics estimator 4 configured to estimate the characteristics of a radio link between the transmitter and the receiver and a carrier quantity determination unit 3 configured to determine the number of carriers according to the result of the estimate by the radio link characteristics estimator 4. The radio link characteristics estimator 4 estimates the characteristics according to an interval in delay time of multipath signals and the number of the multipath signals. The carrier quantity determination unit 3 determines fewer carriers when multipath interference is small, and determines more carriers when the multipath interference is great.