An impact absorbing device for a vehicle may include a bumper beam disposed to extend in a traverse direction of a vehicle, a side member extending in a longitudinal direction of the vehicle and disposed at a lateral side of the vehicle in the traverse direction thereof, a crash box connecting the bumper beam in the longitudinal direction of the vehicle to the side member, a fender apron member disposed at outer sides of the side member in the traverse direction of the vehicle, a connecting member connecting the fender apron member and the side member, and a side crash box of which a front tip end may be mounted to an outer portion of the bumper beam positioned at an outer direction of the side member in the traverse direction of the vehicle, and of which a rear tip end may be disposed to be spaced apart from the connecting member at a predetermined interval therebetween.