A roof is split into plural parts, a front roof and a rear roof. A roof-storage space is formed between a passenger's seat and a rear bulkhead which forms a rear end of a vehicle compartment, in which the roof is stored when the roof is open. There is provided a support mechanism which substantially horizontally supports the roof which is stored in the roof-storage space so that an upper space of the roof-storage space between the passenger's seat and the bulkhead is covered with only one of the plural parts of the roof.