A front end portion 100 is disposed on the front end of a car body. The
floor thereof consists of extruded hollow members 210 that constitute a
shock absorber 200. The shock absorber 200 is divided into an upper shock
absorber 200 and a lower shock absorber 200. Annealed extruded hollow
members are used to form the hollow member 210. The hollow members 210 are
disposed so that their direction of extrusion corresponds to the
longitudinal direction of the car body. The hollow members 210 are divided
longitudinally into two portions by a plate 220. At the width-direction
ends of member 210, the face plates 211 and 212 are welded onto plates
223-226. Upon receiving impact load, members 210 fold up into concertinas,
absorbing the impact force. Since members 210 are separated by a plate,
they deform evenly and continuously into concertinas instead of being bent
in half, capable of absorbing a large energy.