To enable quick opening and closing operation of double doors 5a, 5b without causing a user to feel troublesome even if the user is a person using a wheel chair or a person in the state of being deprived of free use of hands by making it possible to open or close the right and left doors 5a, 5b simultaneously by opening one of the doors 5a, 5b.

A pair of the doors 5a, 5b are provided on right and left positions of a door frame 1. The left door 5a is swung about a left side vertical shaft 6a in a vicinity of a left end and the right door 5b is swung about a right side vertical shaft 6b in a vicinity of a right end. The right and the left doors 5a, 5b are connected by an interlocking mechanism 7. When one of the doors 5a, 5b is opened or closed, the other door 5a, 5b is opened or closed through interlocking.