The present invention relates to a vehicle sunshade device 20, which can cover and uncover a rear window provided between a pair of rear pillars 11R and 11L formed in both sides in the vehicle width direction with a screen body 21, and comprising: a winding device 30 for biasing the screen body 21 in its winding-up direction; a pair of guide rails 40R and 40L in both sides in the vehicle width direction of the winding device 30, and capable of being attached to the inner wall of the rear pillar; a pair of sliders 50 fixed at both edges in the vehicle width direction of the screen body 21 respectively, and capable of reciprocately moving within the pair of guide rails 40R and 40L; a drive unit 60 for reciprocately moving the sliders 50 within the guide rails 40R and 40L so as to spread out the screen body 21 against the biasing force of the winding device 30 and wind up the screen body 21 in a spread-out state with the winding device; a temporary joint part 80 for temporarily connecting the pair of guide rails 40R and 40L with the winding device 30 in a condition, where a relative distance between each of the guide rails 40R and 40L is adjustable, until the present vehicle sunshade device 20 is attached to the pair of rear pillars 11R and 11L.