Relation between impact force on the automobile lamp and its filament deformation are examined experimentally for accident reconstruction. Filament coil axial impact force and impact force perpendicular to the filament coil axis are applied respectively to two types of automobile lamps, one is the energized low-beam headlight lamp (12 V/55 W) and the other is the energized braking stop lamp (12 V/23 W). And the following results were obtained. (1) For impact force perpendicular to the filament coil axis, curve deformations were examined in both types of the lamp filaments. And in also this case, interrelation between the magnitude of impact force and the coil extension quantity were obtained for the two types of lamp filaments respectively. (2) For the filament coil axial impact force, deviations of filament coil pitch were examined in both types of lamp filaments. And in also this case, interrelation between the magnitude of impact force and the standard deviation for filament coil pitch were obtained for the two types of lamp filaments respectively. (3) The deformation rate for headlight low-beam filaments for (1) and (2) mentioned above using each tests, defined as the ratio between the deformation and the initial condition before the impact, is always larger than that of the braking stop lamp filament.