To provide a suspension member fitting structure which can heighten fitting rigidity of a suspension member by a stiffening stay, and hold down the retreat amount of a fitting bolt lower end part to excessive input directing toward the longitudinal direction of the car body at the time of a vehicle collision or the like.

A stiffening stay 10 fitted to a fitting bolt for fitting the rear end part of the suspension member in the longitudinal direction of the car body includes a stay body 13 extended from the fitting position to the fitting bolt in the longitudinal direction of the car body and a projected part 14 projected from the stay body 13 in the cross direction of the car body. The tip part of the projected part 14 is fitted to a member of the car body side. A bolt holding member 16 for regulating the retreat amount of a shaft part of the fitting bolt is fixed to the stiffening stay 10.