PURPOSE: To reduce number of components, to facilitate assembling and recycling of a material by forming a part in contact with an end of a screen at an end of a pawl having spring property in a tapered state and a part in contact with a door body to be higher by an interval between a flat surface of the pawl and a surface of the screen than a door body supporting part.

CONSTITUTION: When a screen 4 is inserted into a groove 3B of an outer frame 3 and a door body is mounted in the frame 3, the body presses protrusions of pawls 3D, 3E to deflect the pawls, and tapered parts 3F of the pawls press the screen 4, thereby effectively holding the screen 4 in the frame 3. The screen 4 is pressed to a protrusion formed at a lower groove of the frame 3 by a pawl 3K formed laterally of the frame 3, and is, since the pawl K has springness, effectively pressed to the protrusion to be held in the frame 3. Accordingly, a double-sided tape, putty is not necessarily used, and not only decomposition is facilitated but also recycling of materials is advantageous.