A touch operation is performed on a touch panel on which a knob for input operation can be placed, using the knob or another operation object. A touch detection unit detects the touch operation in a first detection method and a second detection method which are different from each other. Based on the result of detection in the first detection method, a knob touch point determining unit identifies the position where the touch operation has been performed by the knob, and outputs the touch information. A knob-finger contact determining unit determines whether a finger is in contact with the knob based on the touch information and the result of detection in the second detection method. It is possible to perform, without fail, the determination as to whether a knob or another object is in contact with the touch panel, and whether a finger is in contact with the knob which is in contact with the touch panel.