A fastening apparatus using magnetism enables to fasten an object with a magnetic material to a target surface. The apparatus has a substrate which is flexible and provided at its reverse side with a sticking coat for removably attaching to the target surface, and a magnet receiving hole surrounded by the sticking coat penetrating through the substrate; a flat magnet housed into the magnet receiving hole; an outer film which is fixed on the substrate for separating the flat magnet and the object. The flat magnet is able to be removed out from the magnet receiving hole.