PURPOSE: To allow locking without fully opening a curtain or the like by providing an operation section on a stile of a door stop side without providing a crescent on a meeting stile.

CONSTITUTION: A slider 41 is vertically movably fitted to a stile 25, and a rotary shaft 47 rotated by the vertical movement of the slider 41 is provided over a meeting stile 27 and the stile 25. A pair of pressure contact pieces 49a, 49b pressed with slant faces together and interlocked by friction force when a sash is fastened are provided on a meeting face faced to the meeting stile 27. When the pressure contact pieces 49a, 49b are lowered, moving rods inserted into the first locking holes formed on rails at the tips are fixed to the pressure contact pieces 49a, 49b. When the rotary shaft 47 is rotated in the locking direction of the moving rods, a hook 67 hooked on the second locking hole 69 bored on the meeting stile on the opposite side is fixed to the rotary shaft 47 in the meeting stile 27.