According to one embodiment, there is provided a method for manufacturing a photovoltaic cell. The method includes forming a structure including a pair of electrodes which are arranged apart from each other, and a hetero-junction type photoelectric conversion layer interposed between the electrodes and containing a p-type semiconductor and a n-type semiconductor, and annealing the photoelectric conversion layer thermally while applying an AC voltage having a frequency of 0.01 kHz or more and less than 1 kHz to control a mixed state of the p-type semiconductor and n-type semiconductor in the photoelectric conversion layer.