Disclosed is a shade device capable of blocking a window through a slit formed in a window periphery member. The disclosed shade device is provided with: a winding device having a winding shaft which is supported so as to be capable of rotation around an axis; a shade which has an short edge and long edge opposite to one another, which is attached to the winding shaft at the long edge, and which is capable of being pulled out from and stored in the winding device through the slit; a stay attached to the short edge of the shade; a cover body capable of moving between a closed position in which the slit is partially blocked, and an open position in which the slit is freed; and an coupling mechanism which is configured to be capable of coupling with the rotation of the winding shaft and moving the cover body between the open position and the closed position and which, in the shade storage state, moves the cover body to the closed position so as to block the slit by means of the stay and the cover body.