A multi-chip having an optical interconnection unit is provided. The multi-chip having an optical interconnection unit includes a plurality of silicon chips sequentially stacked, a plurality of optical device arrays on a side of each of the plurality of the silicon chips such that the optical device arrays correspond to each other and a wiring electrically connecting the silicon chip and the optical device array attached to a side of the silicon chip, wherein the corresponding optical device arrays forms an optical connection unit by transmitting and receiving an optical signal between the corresponding optical device arrays in different layers. Each of the optical device arrays includes at least one of a light emitting device and a light receiving device.