Abstract: A display having a touchscreen is coupled to a processor that acquires a plurality of first detection positions on the touchscreen at a predetermined detection interval by an operation medium, calculates a predictive position indicative of a predicted subsequent position of the operation medium based on the plurality of first detection positions, corrects the predictive position based on a plurality of second detection positions and a weighting value, the plurality of second detection positions being a subset of the plurality of first detection positions selected at an interval greater than the predetermined detection interval, the weighting value being based on an angle between at least latest three detection positions among the plurality of second detection positions, and displays, on the display, a trajectory line including the plurality of first detection positions and the corrected predictive position.