To prevent a spare tire mounted from being loosened by providing a pair of cramp members for holding a disc wheel of the spare tire from the upper and lower directions and fixing it to a car body under a swingable condition of the spare tire in the roll and pitch directions around a hub hole.

A head of a bracket 4 is in a curved shape such as a convex shape at an upper side with its central part becoming a top, and a lower washer 5 is fixed to the head. A bolt member 7 is provided with an upper washer 6 and a male thread screwed with a mounting hole for the bracket 4. With this storing structure, a disc wheel 2b is held by both upper and lower clamp members in the vicinity of a hub hole 2c, and a spare tire 2 is supported with the clamp members. When both the washers 5, 6 are bent, at least the swinging of the spare tire 2 in the roll and pitch directions are allowed. Accordingly, it is possible to prevent the spare tire 2 fastened by the clamp members 5, 6 from being loosened.