The bearing has support arm (6) and a hinge rod (7) that are connected with the frame side and wing-side fitting units (4,5) in the horizontal pivot axis. A base portion (11) of wing-side fitting unit is connected to the hinge rod and the support arm. A support portion (12) is connected with a wing (2). The base portion and support portion are provided with common axis (10), and the position of the support portion on the base portion is adjustable.
