The present disclosure provides a secondary battery module capable of optically transmitting measurement data on characteristics of cells forming a battery pack and further reducing a complicated procedure of wiring. The secondary battery module of the present disclosure includes: a battery pack in which a plurality of cell units are connected, each of the cell units including a cell and a light-emitting unit, the cell including a stacked unit and an electrolyte, the light-emitting unit being configured to measure characteristics of the cell and generate an optical signal according to the characteristics; and an optical waveguide into which an optical signal is introduced from the light-emitting unit of each of the cell units, wherein the number of optical waveguides is less than the number of optical signals, and the optical waveguide provides a common optical path through which optical signals are propagated from the light-emitting units provided in the battery pack.