A transmitting apparatus and method in a transmit diversity system, which transmits a plurality of block-coded symbols over a plurality of antennas are provided. The transmitting apparatus includes N+M antennas where N is an integer equal to or greater than two and M is an integer equal to or greater than one; a switch which forwards N-ary block-coded symbols to N-ary antennas of the N+M antennas; and a switch controller which controls switching of the switch, and when a receiving end which receives the N-ary block-coded symbols informs the switch controller of a poor reception state, the switch controller forwards the N-ary block-coded symbols to other N-ary antennas which include at least one antenna different from the N-ary antennas. The block-coded symbols can be transmitted by selectively using more antennas than block-coded symbols.