PURPOSE: To increase the opening degree of a roof upto a full open in plural intermediate steps in a running by sending an openable/closable roof part, a side roof part and a temporarily unmovable roof part into a storage chamber on the rear part of a car in order to release the roof in a convertible status.

CONSTITUTION: A roof part is composed of a front cover 4, a rear cover 5 and a rear roof part 7 and side roof parts 6a, 6b guiding the cover in a guide rail are arranged in both sides of the covers 4, 5. The side roof parts 6a, 6b are pivoted on the rear roof part 7 turnably by an electric device 18 and connected to a front lateral beam 2 detachably/attachably. The front cover 4 is moved backward by an electric device 17 on the rear roof part 7 and placed downward the rear cover part 5 and a cover 11 can be covered on the back of the rear roof part 7 by an electric device 14 and a storage chamber 12 storing an entire roof is arranged.