An object of the present invention is to provide a photoelectric conversion element which exhibits excellent heat resistance and responsiveness, and a photosensor and an imaging device which include the photoelectric conversion element. The photoelectric conversion element of the present invention includes: a transparent conductive film; a conductive film; and a photoelectric conversion film and an electron blocking layer which are disposed between the transparent conductive film and the conductive film, wherein the electron blocking layer contains a compound represented by the following Formula (1).