To hold and load a storage box on a roof carrier for loading a ski boards, etc.

A roof carrier 1 comprises a carrier lower 8 detachably provided in a side end part of a roof 2 of an automobile and a carrier upper 9 supported on an inner side in the direction of car width of the carrier lower 8 with the outside in the direction of car width provided so as to open and close. Two roof carriers 1 are provided at an interval in the forward and backward directions of a car body. A storage box 3 is provided with locking parts 10 protruding to the outside in the forward and backward directions of car body on front and rear side walls which oppose to the forward and backward directions of car body mutually. These front and rear locking parts 10 are held between the carrier lower 8 and the carrier upper 9 of two roof carriers 1, 1.