A simple method that makes it possible to manufacture a highly-workable organic solar cell module having a plurality of connected organic solar cells is provided. The method includes: a first electrode substrate forming step of forming a plurality of first electrode layers on a first substrate to form a first electrode substrate; preparing a single piece of second electrode substrate-forming base material having at least a second electrode layer and capable of being cut into a plurality of second electrode substrates; a functional layer forming step; a cutting step to form a plurality of second electrode substrates; a bonding step so that the first and second electrode substrates are bonded together; and a connecting step of electrically connecting the first electrode layer of one of the organic solar cells to the second electrode layer of another organic solar cell which is adjacent to the one organic solar cell.