A method of initializing a touchscreen panel including a first resistive film having a first electrode and a second electrode provided at corresponding ends thereof in a first direction, a second resistive film having a third electrode and a fourth electrode provided at corresponding ends thereof in a second direction perpendicular to the first direction, a first resistor having a first end connected to the first electrode, and a second resistor having a first end connected to the third electrode, includes (a) measuring a potential with the touchscreen panel being contacted at two points with a predetermined potential being applied to the touchscreen panel; and (b) calculating a relational expression between the potential and a distance between the two points based on the measured potential.