Shield device and roll screen

Provided are a shield device that has a light shielding fin that allows a prescribed fabric to be attached and that improves designability and usability, and a roll screen. A roll screen 1 constituting this screen device comprises: a winding pipe 3 that supports a screen 4 so as to be able to open and close by way of winding and unwinding the screen 4; a frame (a mounting frame 2 and a support member 2a, 2b) that supports the winding pipe 3; and a light shielding fin 9 that shields external light entering between the frame and the winding pipe 3. A locking unit 20 for locking the light shielding fin 9 is provided on the frame. The light shielding fin 9 comprises an elastically deformable gripping means (a projecting piece 96a and a claw 99) for gripping the upper end of a prescribed fabric 13. In addition, this roll screen 1 comprises a fin (light shielding fin 9) for covering a gap between the winding pipe 3 and the mounting frame 2, and the mounting frame 2 is mounted to a wall face outside the window frame with fixing hardware 61.