When a gesture operation of a hand moving close to a display from left to right is performed, the return movement of the hand to the left side due to reflection by the wrist or the like may be detected. A detection control unit detects the approach of the hand to the display and notifies a data processing device of non-detection of hand approach when the amount of movement of the hand in the right direction starts to decrease after exceeding a threshold value. The data processing device accepts the right-moving gesture operation to perform a predetermined process when the amount of movement exceeds the threshold value.