A mounting structure that absorbs positional variations occurring in more directions between the centers of a pin and a female mounting member, thereby the structure can be suitably applied to mount an object. An elongated hole-like male side fitting part (36) is so formed that a cap pin (26) can be rotated in the direction of an arrow (R1) and moved (slid) in the direction of the slide axis (X2)relative to the pin (28). Since the cap pin (26) is slid while rotating even if the pin axis (X1) of the pin (28) is deviated from the center axis (X4) of a clip (24), the pin (28) can be inserted and fitted into a male side insertion part (36).