According to a flexible OLED device production method of the present disclosure, after an intermediate region (30i) and flexible substrate regions (30d) of a plastic film (30) of a multilayer stack (100) are divided from one another, the interface between the flexible substrate regions (30d) and a glass base (10) is irradiated with laser light. The multilayer stack (100) is separated into a first portion (110) and a second portion (120) while the multilayer stack (100) is in contact with a stage (212). The first portion (110) includes a plurality of OLED devices (1000) which are in contact with the stage (212). The OLED devices (1000) include a plurality of functional layer regions (20) and the flexible substrate regions (30d). The second portion (120) includes the glass base (10) and the intermediate region (30i).