PURPOSE: To properly prevent a screw from being loosened and falling via the application of simple constitution without any need of forming a screw recess section.

CONSTITUTION: An elastic member 21 having a mounting hole 24 of diameter (d) smaller than the male thread outer diameter D of a screw 7 is laid on the surface of a panel 2 and fastened with a cap 20. Then, the screw 7 is threaded into the mounting hole 24 of the member 21 and the tapped hole 5 of a frame 4, thereby fastening the panel 2 to the frame 4. In this case, the member 21 is elastically deformed in a direction for diameter expansion, and holds the screw 7 with the restoring force thereof. The screw 7 is thereby prevented from being loosened and falling.