An apparatus for realizing a three-dimensional (3D) neural network includes a culture substrate (21) having a 3D structure and a plurality of microelectrodes (22) disposed on the culture substrate (21) in such a manner that neurons are cultured with a 3D structure. The central portion of the culture substrate (21) is shaped in a hemispheric form and a peripheral portion is shaped in a planar form. A plurality of outside connection electrodes (23) are disposed on the peripheral portion so as to be connected to an external device, and a plurality of electrode-connecting lines (24) connecting the microelectrodes (22) to the outside connection electrodes (23) are disposed on the culture substrate (21) as well.