A container assembly for accommodating an electronic device in a panel, includes: a retainer attached to the panel; a cover with the electronic device attached thereto pivotably attached to the retainer, and pivotable between an open position and a closed position; a lock for locking the cover at the closed position; a gear damper; a rotating shelf attached to the cover and sandwiching the electronic device with the cover, a rack formed on the rotating shelf configured for engaging with the gear damper; and an elastic support sandwiched between the retainer and the rotating shelf for biasing the cover to the open position via restoring force of the elastic support; wherein the gear damper depresses the restoring force of the elastic support.