To eliminate uneasiness of mounting to the utmost by preventing the slippage of a pierce sufficiently and moreover, enable easy and effective application of the existing pierce.

There are arranged a base body 1 which is made up of a plate- shaped magnet 1' with rubber-like elasticity while having an insertion hole 11 at a pin 32 of pierce and an adhesive surface 12 which is stuck on the face on the sticking side of the pin 32 with the pin 32 inserted into the insertion hole 11 and a latch member 2 comprising a rubber-like elastic material having an insertion hole 21 into which the pin 32 in the pierce is putted from the tip side thereof 32. The latch member 2 has a permanent magnet 23 which is attracted by a magnetic force of the base body 1 stuck on the pierce and the surface facing the base body 1 in the permanent magnet 23 is covered at least with a rubber-like elastic material.