A packing member includes a first recessed portion, a second recessed portion, a first flange connected to the first recessed portion at a first end, and a second flange connected to the second recessed portion at a first end. The first flange includes at least one first bent portion protruding in a direction intersecting a joined surface at which part of the first flange and part of the second flange are joined. When at least one of a second end of the first flange and a second end of the second flange is in contact with a surface other than the packing member, the second end of the first flange and the second end of the second flange can be moved along the surface.