To provide a wheel arch structure in which a wheel arch protector is attached to a wheel arch with accuracy and easily, and to provide an assembly method of the same.

The wheel arch structure is made by assembling a wheel arch protector 6 to a wheel arch formed in an arc shape across from an outer panel to a rear bumper. The wheel arch protector 6 includes: a protector body 61 which is formed in an arc shape; a plurality of clips 62; and an engaging claw 66 which is provided at a lower end of the protector body 61 on the bumper side. The outer panel includes a plurality of clip holes, each of which is connected to a part of the plurality of clips 62. The rear bumper includes: a plurality of clip holes, each of which is connected to the other part of the plurality of clips 62; and an engaging part 58 which is provided at a lower end of the rear bumper and with which the engaging claw 66 is engaged.