To provide a shock absorbing member to solve a problem on a shock absorbing member using a conventional aluminum extruded material, and obtain the member which is excellent in shock absorbing performance, indicates a stable deformation mode, and enables easy and efficient production.

The shock absorbing member is formed of aluminum alloy casting in which a hollow part is formed and the thickness of the hollow part is changed continuously or partially along an axial direction. By continuously or partially changing the thickness of the hollow part along an axial direction by the aluminum alloy casting, the hollow part is axially plastically deformed in a bellows-form state in a specified deformation mode to obtain the shock absorbing member lightweight and excellent in shock absorbing capacity. Further, since it is manufactured by casting, the change of a sectional shape is facilitated in comparison with a conventional method to be manufactured into an extrusion material, and a flange can also integrally be formed through a single casting process.