An optical electric field enhancing device is used with a measuring method which includes two-dimensionally scanning a surface in in-plane direction of the surface to detect, from the rear surface side of the device, signal light emitted from each scanning point when excitation light is applied, and obtaining a two-dimensional signal image on the surface based on the detected signal light. The device includes a transparent substrate, a marker pattern directly formed on the transparent substrate and extending in a direction non-parallel to the main scanning direction of the two-dimensional scanning, and fine uneven structures formed on the marker pattern and the transparent substrate where at least the surface is made of a metal film.