Provided are a digital radio frequency (RF) converter and an RF converting method thereof. The RF frequency converter includes first and second RF output terminals of a differential form outputting an RF signal; a differential switch selectively connecting first and second nodes into the first and second RF output terminals in response to an oscillating waveform; at least one digital delay device column outputting a plurality of unit bits by sequentially delaying an input bit corresponding to the digital input signal; a front-end processor summing an output of the at least one digital delay device column; a plurality of current sources; and a plurality of first switches corresponding to the plurality of current sources, respectively, and delivering currents of current sources whose number corresponds to the sum value of the front-end processor among the plurality of current sources, to one of the first and second nodes.