PURPOSE: To regulate the opening degree of a door to a desired angle by a method in which the end of a stay is coupled through a guide pin with the long hole of a position adjustable fitting metal and the other end is rotatably attached to the door.

CONSTITUTION: A fitting long hole 2b is horizontally formed in the front upper end 2a of a box 2 whose front side is opened, and an angled fitting steel metal 8 is attached through a tiered washer 10 and a fitting screw 12 to a position along the hole 2b in a position adjustable manner. One end of a stay 14 is coupled through a guide pin 16 to the long hole 8b of the metal 8, and the other end is attached rotatably to a door 6. The screw 12 is loosened to adjust the position of the metal 8, and the screw 12 is clamped to regulate the opening degree 6a of the door 6 to a desired angle through the stay 14.