PURPOSE: To change the bearing capacity of an energizing member by simple operation and also to make the bearing capacity of the energizing member steplessly changeable in a door which is so constructed that the energizing member for energizing a door body upward is installed in a void in a strut.

CONSTITUTION: In a bascule type door which is so constructed that an arm 2 to which a door body is fitted is freely turned in an arc vertically and further an energizing member 4 for energizing the arm 2 upward is disposed in a strut 1, one end part 51 of an adjusting arm 5 is fixed to the shaft 10 of the arm 2 in the strut 1. One end part 41 of the energizing member 4 is connected to the other end part 52 side of the adjust arm 5 through a bolt 6, and the bolt 6 can be screw turned from the outside of the strut 1. The energizing member 4 is expanded and contracted by operating the bolt 6 to adjust the bearing capacity of the energizing member 4.