To obtain accurate coordinate data even when chatter occurs in a touch panel device.

At the time of converting a measured voltage value measured according to a touch position when a touch panel is touched into the coordinate data of the touch position, and outputting the coordinate data, when the touch panel is touched, a measured voltage value is measured plural times, and the first measured voltage value is defined as a reference voltage value, and the second and following measured voltage values are defined as comparison voltage values. The reference voltage value and the comparison voltage values are successively compared, and when they are continuously matched the preliminarily decided specific number of times, the reference voltage value or the comparison value are converted into coordinate data.