The invention relates to a method and a device (1) for assembling a transformer (10). A transformer core (6) of the transformer can be arranged in a receiving portion (3), and a coil (5) lies around the transformer core. According to the invention, a device is provided for assembling a transformer, wherein the receiving portion can be arranged within a lifting platform (2) that has lifting platform-adjusting elements (7), said adjusting elements being movable relative to each other.