To enable locking having high reliability by penetrating a shape memory coil into a penetrating hole disposed on a locking member, when a part of a micro shape memory metallic coil is locked, and screwing a locking coil one side or both sides of a shape memory coil part positioned in the penetrating hole.

A helical shape memory coil (an SM coil) 2 are penetrated in a through-hole 4 disposed on a locking member 3, and a locking coil 1 is screwed in a right side part 21 in parts 21, 22 which are continued to both sides of an SM coil part 29 positioned in the through-hole 4, so as to be brought into contact the end surface 11 of the locking coil 1 with an end surface 391 of a sidewall 39 of the locking member 3. Since the locking coil 1 has a coil outer diameter d1 which is larger than an inner diameter d5 of the through-hole 4 by Δ1, the end surface 11 of the locking coil 1 is hung up to the end surface 391 of the side wall 39 of the locking member 3, even if the SM coil 2 is pulled in the arrow A direction. It is thus possible to surely obstruct movement of the right part 21 toward the arrow A direction.