PURPOSE: To form a precise outside angle by preventing the outside angle of a form from being willing to separated through utilization of wales installed on the form, and to accomplish a structure serviceable irrespective of the position of the wales which are in place.

CONSTITUTION: A fixture for outside angle according to the invention consists of two fixation parts 2, which are stretched over wales 41, 42 interseting at the outside angle and hold them firmly, and a coupling rod 3 to couple these fixation parts. At least one of the fixation parts 2 is installed rotatable relative to the coupling rod 3 so as to provide changeability for the angle formed by the wales 41, 42 to the coupling rod 3.