Abstract: A bumper mounting structure in which a vertical parting line is defined between a bumper and a part of a vehicle body such as a fender. In order to control the width of the parting line, the mounting structure comprises a first member attached to the bumper, a second member attached to the fender and coupled to the first member for sliding engagement therebetween so as to permit a relative motion along the fore-and-aft direction of the vehicle body, and a screw member threaded to one of the members and abuts the other member for adjusting the relative distance therebetween. By turning this screw member, the width of the vertical parting line can be adjusted to an optimum value and a favorable unified appearance is produced between the bumper and the fender.