A sunshade device includes a pair of shade guide rails across an indoor opening; a shade of which opposite side edges are guided by the shade guide rails; and a winding shaft rolling up the shade, wherein the opposite side edges of the shade are guided by the shade guide rails with the side edges being folded after a folding stroke whose folded width is gradually increased toward a front end of the shade when the shade is drawn out from the winding shaft, each of the opposite side edges of the shade is provided with a folded introduction part formed by folding a side edge portion of the shade and connecting the folded side edge portion to a main body portion of the shade, and the folded introduction part is formed in a predetermined length from the front end of the shade in an open/close direction of the shade.