An armrest touch screen device with a water discharge function applied to a vehicle according to the present disclosure includes one or more of: a water discharge part defined by a touch screen panel and a screen body; a fitting coupling part defined by the touch screen panel and the screen body; a bolting fastening part defined by the touch screen panel, the screen body, a circuit board, and a screen casing; and a hook engaging part defined by the screen body and a screen casing. Accordingly, it is possible to prevent water permeation into the touch screen panel, reduce the weight and the material costs by reducing the number of screws, implement the robust touch screen design, and minimize the assembly dimension error.