To prevent the erroneous determination of the manner of manipulating by individually monitoring the capacitances of conductors each including a first electrode and a first conductive line which are mutually connected.

In the touch pad device, electrodes E1 and E2 are formed on a substrate SB1. Electrodes E3-E10 are formed on the substrate SB1 to surround the electrodes E1 and E2. Conductive lines L1 and L2 extends over the substrate SB1 to sandwich the electrodes E6 and E7, and are connectedto the electrodes E1 and E2, respectively. An insulating sheet, having a surface exposed to the outside, covers the electrodes E1-E10 and conductive lines L1-L10. If the electrodes E1 and E2 exist on the reverse side of the contact part when an operator's finger contacts the insulating sheet, the capacitances of a conductor EC1 and a conductor EC2 are changed. Similarly, If the electrode E7 and the conductive line L1 extending in its vicinity exists on the reverse side of the contact part when the operator's finger contact the insulating sheet, the capacitances of a conductor EC7 and a conductor EC1 are changed. Accordingly, the conductive lines L1-L2 are formed on the substrate SB1 to sandwich the electrodes E6-E7, whereby the erroneous determination of the manner of manipulating can be prevented.