To provide a vehicular door window opening/closing device which can open a vehicular door window only by a small amount, by carrying out simple instruction operation.

According to the vehicular door window opening/closing device, when a small-amount opening switch 13 is pressed, a door ECU 1 outputs a driving signal to a window driving motor 14 to set the door window in a slightly (e.g. on the order of 3 cm) opened state (small-amount opening state). Thus if the user wants to slightly open the door window for ventilation of air in a cabin, for instance, only by pressing the small-amount opening switch 13, the vehicular door window is set in the slightly opened state (small-amount opening state). Therefore the user is free from an inconvenience of adjusting the opening amount of the door window by intermittently pressing a door window opening/closing key by a slight amount, which improves the operability of the door window.