To improve a shock absorbing structure mounted on a floor body structure of a railway vehicle to absorb the shock at collision.

This shock absorbing structure 200 is provided with a body structure constituted into a square columnar shape having a length dimension L1 by joining four sheets of hollow extruded materials 210, 220, 230 and 240 by a welding part W2. The hollow extruded material 220 has a structure for connecting an outer plate 221 and an inner plate 222 by a truss 223. The other hollow extruded materials 210, 230 and 240 have the same structure. Both of the hollow extruded materials 210, 220, 230 and 240 and filler metal of the welding part W2 are made of 6000 based aluminum alloy. By this structure, each part in the structural body 200 is uniformly compressed and deformed to improve a shock absorbing characteristic.