PURPOSE: To open and close a comparatively large opening part by a comparatively small door member by interlocking and connecting two pieces of the door members to close the opening part when they make contact with each other and opening and closing the other door in accordance with opening and closing of the one door member.

CONSTITUTION: An opening part 2, for example, formed on the left side of a vehicle is extended backward from a window 4 and an arm 5 for a wheel and arranged between a roof 7 and a door sil part 9. In this case, a door structure to open and close this opening part 2 is formed of front and rear door members 10, 11 to close the opening part 2 by making contact with each other. Additionally, the rear part door member 11 forms a track guide 15 on an upper end part of a lower part panel 12, and a support element 16 projected from a car body is inserted into the track guide 15. Furthermore, the rear part door member 11 is connected to the car body through a two arm link 19, and an intermediate part of the two arm link is interlocked and connected to the front part door member 10.