To provide a cover for blocking an opening part which can increase force for pulling-out the cover without reducing fixing workability thereof.

There are provided a first member 8 and a second member 9 so as to block an opening 4 of a suspension tower top wall 2. The first member 8 is formed into a ring-shape in correspondence with the opening 4 and its lower part has a plurality of engaging claws 15 to be engaged with an inner peripheral edge 5a of the opening 4. The second member 9 has integrally an insertion part inserted into the first member 8 to establish its restricted state in regard to a relative turning motion and a moving-away motion with respect to the first member 8 under an engaged relation with the first member 8, and a lid part for covering an opening 25 of the first member 8.