Provided are an apparatus for addition data transmission includes: an IF broadcasting signal generating unit receiving the broadcast data, and FEC and modulation of the received broadcast data to generate a broadcasting signal in an intermediate frequency (IF) band; an IF addition signal generating unit receiving the addition data to generate an addition signal in the IF band by using direct sequence spread spectrum (DSSS); an average power controlling unit controlling average power of the addition signal in the IF band; a signal combining unit combining the broadcasting signal in the IF band and the addition signal in the IF band to generate a combination signal; an RF upward converting unit upwardly converting the combination signal in a signal in a radio frequency (RF) band to a combination signal in the RF band; and a transmitting unit transmitting the combination signal in the RF band.