PURPOSE: To improve workability by arranging a cylindrical body in a continuous manner to a small hole for positioning, and inserting a rodlike jig into the cylindrical body, thereby adjusting the mounting position of a fixing plate.

CONSTITUTION: A lock body 103 is installed in an inner sash 100, and under a condition where a knob 112 is raised from the slit 109 of a second fixing plate 108a rodlike jig 2 is inserted into a small hole 11 of a movable plate 113 and a small hole 116 of a first fixing plate 107, and then the tip of rodlike jig 2 is inserted into the cylindrical body 1 of a receiving member 106. The body 1 is restricted by the rodlike jig 2, and the cylindrical body 1 moves so that it may be continous to each hole 117, 16 of lock main body 103. Thereafter, the jig 2 is pulled off from the cylindrical body and each hole 116, 117 of the lock main body 103, and the inner sash and an outer sash 101 are separated from each other, and a receiving member 106 is tightened to the outer sash 101.