There is a need for a detection device which has high photoreceptive sensitivity in a generally wide frequency region including the infrared region. Therefore, in the present invention, by utilizing a phenomenon in which electric field strength is enhanced by surface plasmon resonance in a negative dielectric constant medium, a detection device is provided which has an electromagnetic wave detection portion disposed at a position where the electric field strength is large. The device includes a filter portion for selecting a wavelength region of an electromagnetic wave to be detected and an electromagnetic wave detection portion (103). The filter portion includes a first medium (101) having a dielectric constant with a negative real part and a second medium (102) which is different from the first medium. The distance between the first medium and the second medium is not more than a wavelength of the electromagnetic wave to be detected, and the distance between the first medium and the electromagnetic wave detection portion is not more than the wavelength of the electromagnetic wave to be detected.