This paper proposes a partial spectrum retransmission scheme using a dynamic spectrum control for broadband single carrier transmission systems. In the proposed scheme, using a dynamic spectrum control in which discrete spectrum of the transmitted signal is mapped onto an arbitrary part of the assigned spectrum, only a certain amount of deeply faded spectrum components are retransmitted via a part of channel having relatively a higher channel gain. The amount of retransmitted components are determined based on mutual information between the transmitted signal and the output of an minimum mean square error (MMSE) based frequency domain equalizer (FDE). Moreover, plural retransmission frames are multiplexed in a retransmitted frame for efficient utilization of the retransmitted spectrum component reduction. Computer simulation confirms that the proposed scheme can achieve high throughput performances even under low terminal mobility or quasi-static conditions.