To surely and easily put on/off a lowered lid for a transporting container from the container without degrading its dustproof function.

The lowered lid to be put into an opening surface of the container for closing the opening is formed by making flexible wing-formed parts overhang sideward around a lid equipped with uneven parts on the upper surface. A cut is provided in the wing-formed part on at least part of the periphery of the lid to make the lowered lid easy to remove from the container.