To provide a vehicle accident analyzing apparatus in which reconstruction quality of low speed crashes is improved. An impact parameter determination apparatus 10 is provided with a triggering unit 20 which uses input signals from in-vehicle sensors, and an area determination unit 30, and a parameter calculation unit 50. The triggering unit 20 generates a trigger signal 21 based on the input signals for triggering the area determination unit 30 and the parameter calculation unit 50. The area determination unit 30 uses the input signals to calculate the most probable impact area 31. The parameter calculation unit 50 calculates the final desired crash parameters based on the input signals and the most probable impact area 31.