1. An input device comprising: an input mechanism to detect a variation of capacitances at a plurality of detection points; and a control unit to calculate detection outputs from the plurality of detection points to determine a peak position in the variation of capacitances and to generate coordinate data from the peak position, wherein the peak position is determined using a maximum value detected at any one of the detection points, a previous value detected at at least one previous point to the detection point at which the maximum value is obtained, and a following value detected at at least one point which follows the detection point at which the maximum value is obtained, and said control unit outputs the coordinate data only when a variation of the maximum value varies from the previous value and the following value is greater than a first threshold value.