PURPOSE: To facilitate the anchor work to a PC concrete panel by imparting elasticity to the leg parts, inserted between both projecting pieces, of an anchor, and fitting the anchor to a frame member by the restoring force of always enlarging the distance between the projecting pieces.

CONSTITUTION: Plates and ribs are protrusively provided at intermediate parts 12 excluding both leg parts 11, 11 in order to obtain anchoring performance to concrete 42. The tips of the leg parts 11, 11 are bent so as to be engaged with fins 32, 32 bent in the opposed direction from projecting pieces 31, 31 in order to prevent a sash 2 from slipping out onto the outer peripheral side from a frame member 3. In the longitudinal direction of the frame member 3, slip-off is prevented by making the leg parts 11, 11 butt the orthogonal frame member 3. The intermediate part 12 of an anchor 1 is provided with an opening 13 so as to make concrete 42 come around better to the frame member 3 side at the time of filling the concrete 42. In this case, both leg parts 11, 11 are compressed in the opposed direction to insert the anchor 1 between the projecting pieces 31, 31. The leg parts 11, 11 further press the projecting pieces 31, 31 by the restoring force of enlarging the distance between the projecting pieces 31, 31 so as to ensure the fitted state.