1. A touch sensor device comprising: a transparent conductive layer forming an impedance surface, the impedance surface including an active area where a human body can touch or approach, a plurality of sets of reference coordinates being set at a plurality of locations in the active area; a plurality of detection electrodes arranged on the impedance surface; a detection circuit configured to detect electric currents passing the detection electrodes; a storage section storing reference standardized values and reference normalized values, the reference standardized values corresponding to estimated coordinates of each set of the reference coordinates, the reference standardized values being calculated by obtaining electric currents detected by the detection circuit on each set of the reference coordinates being pointed with one pointer and by standardizing the detected electric currents for each set of the reference coordinates, the reference normalized values being calculated by normalizing the detected electric currents so as to make a total sum of the electric currents passing the impedance surface a constant value, for each set of the reference coordinates; a position coordinate calculation section configured to obtain standardized values calculated by standardizing the electric currents detected by the detection circuit in each detection period and to map the standardized values onto position coordinates on a basis of a relation between the reference standardized values stored in advance in the storage section and the reference coordinates; a first normalized value calculation section configured to map the position coordinates onto first normalized values on a basis of a relation between the reference coordinates and the reference normalized values; a second normalized value calculation section configured to calculate second normalized values by normalizing the electric currents detected by the detection circuit in each detection period; and a touch gesture detection section configured to detect a motion of a plurality of pointers on a basis of a time variation of the first normalized values and the second normalized values.