<p>[Problem] To provide a thin film forming device that can shorten work time during film forming and reduce costs in film forming work by simplifying and making more efficient work for forming thin films only on specific parts on a plurality of substrates. [Solution] A substrate holding mechanism (3) provided in a thin film forming device (100) is provided with: substrate holding members (10-40) that hold a plurality of substrates (S) such that some parts (S2) where the film will not be formed on the substrate (S) overlap each other and parts (S1) for film forming are exposed; support members (50) that support the substrate holding members (10-40); and a rotating member (60) that rotates the support members (50). The substrate holding members (10-40) have: a plurality of holding surfaces (11d) that hold a plurality of substrates (S) and are disposed between a film forming source (4) and the plurality of substrates (S); a plurality of stepped parts (11e) formed between the plurality of holding surfaces (11d) and in contact with each of the end parts of the plurality of substrates (S); and a plurality of opening parts (11f) formed on parts of the holding surfaces (11d) that correspond to the parts (S1) for film forming in a state in which the end parts of the plurality of substrates (S) are in contact with the plurality of stepped parts (11e).</p>
