The present invention relates to a method for manufacturing: a perovskite solar cell in which the laminated shape and the composition of a perovskite absorbing layer are controlled; and a tandem solar cell comprising the perovskite solar cell, and the perovskite absorbing layer is formed through a method for manufacturing a solar cell, comprising the steps of: forming, on a substrate, an inorganic seed layer conformal with the substrate by using a BO source, an A-doped BO source or an AxOy source and the BO source; and supplying organic halides onto the seed layer, and thus a perovskite thin film having a complex composition conformal with the substrate can be formed such that an effect of enabling light absorption to increase can be achieved.