A method for manufacturing a photoelectric conversion device of an embodiment includes forming, on a first electrode, a photoelectric conversion layer comprising at least one of a chalcopyrite compound, a stannite compound, and a kesterite compound. The forming of the photoelectric conversion layer includes forming a photoelectric conversion layer precursor comprising at least one compound semiconductor of a chalcopyrite compound, a stannite compound, and a kesterite compound on the first electrode. The forming of the photoelectric conversion layer includes immersing the precursor in a liquid including at least one of Group IIa and Group IIb elements at 0° C. to 60° C., after forming of the photoelectric conversion layer precursor. The compound semiconductor on a side of the first electrode is at least either amorphous or larger in average crystal grain size than the compound semiconductor on an opposite side of the first electrode.