An object of the present invention is to provide an emission marker for being indwelled in a lumen, the emission marker having: a base part； a coil wound around the base part； an emission part electrically connected to the coil； and a cover part for covering at least the base part and the coil, wherein the emission part has a light source that emits visible light. Additionally, the present invention relates to a detector for detecting, from outside of a lumen, an emission marker indwelled in the lumen, the detector having a detection unit having an antenna that acts with a coil of the emission marker.
