Impact absorbing body

An impact absorber comprising a hollow blow molded article, wherein

• the blow molded article includes a front wall and a back wall separated into front and back and facing each other and a side wall connecting the front wall with the back wall,
• the front wall includes a tubular front side concave rib formed by indenting the front wall, the back wall includes a tubular back side concave rib formed by indenting the back wall, and the front side concave rib and the back side concave rib have distal end portions welded to each other,
• at least one of the front side concave rib and the back side concave rib has a buckling induction section formed as origin of buckling for impact absorption, and
• when a load is applied in an axial direction of the front side concave rib and the back side concave rib, the at least one of the front side concave rib and the back side concave rib is configured to cause at least one of center of gravity of an opening surrounded by an opening edge of the front side concave rib and center of gravity of an opening surrounded by an opening edge of the back side concave rib to buckle in a mode of moving in a direction crossing the axial direction by the buckling induction section.