In the IEEE802.11 wireless local-area network (WLAN), the TCP throughput unfairness will appear when multiple hosts concurrently communicate with a single access-point (AP), since the TCP window size, the modulation and coding scheme (MCS), and the packet drop rate become different among them. In this paper, we propose a TCP fairness control method using the transmission delay in WLAN. The target throughput is introduced as the equal throughput, which will be dynamically updated with measured throughputs. Then, the delay is controlled by the PI feedback control such that the measured throughput is equal to the target. The effectiveness is confirmed through experiments using our elastic WLAN system testbed with one AP and up to four hosts, where all the hosts have achieved the similar throughputs based upon the proposal.