To provide an easily and safely detachably stud which does not required the pressure penetration of a needle but holes a paper piece securely and stably like a picture stud and can be attached/detached easily and safely like a magnet stud.

This magnetized stud system consists of a magnetized stud with a stud needle part 5 formed on the magnetizable face of a magnet and a magnetic display board 12 which has a display retaining hole 13, through which the stud needle part 5 is introduced. A metal stud and a multiple stud consisting of a magnetizable elements on both faces with a center retaining hole 12, through which the stud needle part 5 is introduced and retained are used. A paper piece can be securely retained stably by magnetic attraction only by introducing the stud needle part 5 which penetrates through the paper piece into the space of the retaining holes 12, 13. In addition, the stud can be easily removed in safety from the retaining holes 12, 13.