To realize an electromagnetic field generating element, an information recording and reproducing head and an information recording and reproducing device for high frequency magnetic recording and reproducing by the optically assisted magnetic recording and reproduction using near field, which permit attenuation or delay of a magnetic field to be suppressed, the electromagnetic field generating element of the present invention generates a magnetic field in a direction parallel to the surface of a constricting section by supplying current in the conductive member, and applying a laser beam from the side of the substrate to the constricting section, and a surface plasmon is excited by an magnetic field vector vertical to the surface of the constricting section, thereby generating near field from the surface facing the interface between the substrate and the constricting section.