A readout integrated circuit (ROIC) for a touch screen, the readout integrated circuit includes: a touch sensor unit configured to include a plurality of touch sensors which are arranged in a matrix form having rows and columns in an inside or outside of a touch screen panel (TSP); a plurality of sensing blocks configured to sense an electrical change in each of the touch sensors, to convert the electrical change into a voltage value, and to store the voltage value; a delta circuit unit configured to receive a difference between two sensing voltage values stored in two sensing blocks, respectively, which are spaced by a predetermined distance and selected from among the plurality of sensing blocks, and to produce a delta (Δ) voltage; and an analog-to-digital converter configured to convert an analog signal output from the delta circuit unit into an N-bit digital signal (wherein, “N” is a natural number).