A signal detection device according to an aspect of the invention includes a laminated structure of a first circuit layer (201) in which a plurality of electrodes brought into contact with a subject is formed, a second circuit layer (202) in which a plurality of amplifiers having an input portion capacitively coupled to the plurality of electrodes, respectively, is formed, and a third circuit layer (203) in which a plurality of transistors for reading outputs of the plurality of amplifiers is formed, an insulation layer which seals the second circuit layer is formed between the plurality of electrodes formed in the first circuit layer and the second circuit layer, and the plurality of electrodes and the input portions of the plurality of amplifiers are capacitively coupled to each other via the insulation layer.