Disclosed herein is a digitizer, including: an input unit in which a magnet is embedded; a driving coil in which source supplies to induce a line of magnetic force; a sensing coil in which voltage or current is induced by the line of magnetic force; and a controlling unit supplying the source to the driving coil and measuring the voltage or the current induced in the sensing coil, wherein the controlling unit senses a change amount in the voltage or the current induced in the sensing coil to calculate a coordinate, when the voltage or the current induced in the sensing coil is changed by the magnet.