A probe (100) is provided with: a substrate (110) having a surface facing a medium (20); and a point electrode (120), formed in the substrate, for performing at least one of detection operation of a state of a domain of the medium and change operation of the state of the domain of the medium, a tip portion, which is an edge portion on a side facing the medium, out of the point electrode being disposed in one point in a plane which is formed in a vicinity of an area portion in which the point electrode is formed by the surface.