A mounting structure of an impact absorbing pad mounted to a back surface of an interior lining, which makes it possible to facilitate positioning and mounting of the impact absorbing pad, and which enhances durability of the impact absorbing pad by preventing breakage of the impact absorbing pad when an impact load is applied from a lateral direction of an indoor side of a vehicle.A box-shaped holder is vertically provided at a mounting reference position of a back surface of a door lining body in a door lining (interior lining), an insertion piece in an impact absorbing pad is fitted in the above described box-shaped holder, and positioning and fixing at a reference fixing point of the impact absorbing pad performed. Then, by giving flexibility along a load direction to a top plate part of the above described box-shaped holder, the above described top plate part is bent when an impact load is applied from the lateral direction of the indoor side of the vehicle, whereby an excessive load applied to the top surface of the insertion piece can be reduced, and durability of the impact absorbing pad is enhanced.