PURPOSE: To improve the durability of a frame device and to reduce the cost of the frame device by fixing the nut member having the screw hole communicating to a through-hole and a thrusting hole, onto the connecting plate of a fitting holder.

CONSTITUTION: A fitting holder 28 composed of leg parts 26 and the connecting plate 27 laid across the interval between these leg parts 26, is fixed to the peripheral position of the through hole 23 bored on both side frames 24 of an outer mold 21. On said connecting plate 27 of this fitting holder 28, a thrusting hole 29 is provided at the position connecting to the through-hole 23. Further, a nut member 30 is fixed to this connecting plate 27. The screw hole 31 formed inside of this nut member 30 is connected to the through hole 23 and the connecting hole 29. Consequently, when the frame is filled with concrete milk 13, even if the concrete milk leaks from the through-hole bored on the side frame 24, the screw hole 31 of the nut part 30 will not be broken at all.