A detection device includes a substrate, a plurality of photodiodes that are provided on the substrate, and include organic semiconductors, a plurality of transistors that are provided correspondingly to the respective photodiodes, and each include a semiconductor layer, a gate electrode, and a source electrode, a plurality of lower electrodes that are provided between the transistors and the photodiodes in a direction orthogonal to the substrate, and are provided correspondingly to the respective photodiodes, an upper electrode provided across the photodiodes, a first auxiliary capacitor electrode provided between the substrate and each of the photodiodes in the direction orthogonal to the substrate, and a second auxiliary capacitor electrode that is provided in the same layer as that of the semiconductor layer or the source electrode, and faces the first auxiliary capacitor electrode with an insulating film interposed between the first auxiliary capacitor electrode and the second auxiliary capacitor electrode.