pads 23a and 23b of the shock absorbing unit 23 with permanent dents or the like when a comparatively large impact force is applied in the direction of the arrow a to the shock absorbing unit 23 by the passenger or the like such as luggage forced to move laterally toward the side door 21 by a lateral collision of the vehicle the comparatively large impact force is transmitted through the hard members 34 to the shock absorbing pads 23a and 23b and then the shock absorbing pads 23a and 23b collapse on the side door 21 to absorb the energy of such impact force the hard members 34 are forced to move toward the side door 21 without being broken to support the passenger or the like such as luggage accordingly the passenger will not be injured and the luggage will not be damaged by deformed or broken hard members 34 the soft flexible sponge layer 35 further ensures the safety of the passenger or the luggage an impact energy absorbing structure of a second embodiment according to the present invention comprises a shock absorbing unit 23 comprising a chest protecting shock absorbing pad 23a and a lumbar region protecting shock absorbing pad 23b and having a construction substantially the same as that of the shock absorbing unit 23 of the first embodiment shown in fig6 to 9 the shock absorbing unit 23 is provided on a trim board or panel 29 attached to the door inner.