According to one embodiment, the touch drive device includes a plurality of drive electrodes arranged side by side to extend in a single direction, a detection electrode which extends in a direction crossing the direction in which the drive electrodes extend, and generates capacitances at intersections of the detection electrode and the drive electrodes, and a driver (DDI) which groups the drive electrodes into a plurality of drive electrode portions each including at least one drive electrode, and performs a touch scanning drive by supplying a touch drive signal (TSVCOM) having a pulse waveform for detection of a closely situated external object to a target drive electrode portion which is a selected one of the drive electrode portions. The number of the drive electrodes included in each of the drive electrode portions and the target drive electrode portion to which the touch drive signal. (TSVCOM) is supplied can be designated.