Disclosed is a method of manufacturing a compound semiconductor solar cell including forming a compound semiconductor layer; and forming a defect-removed portion formed of an empty space through removing a portion of the compound semiconductor layer where a defect existed prior to removal. The forming of the defect-removed portion includes forming a mask material layer on the compound semiconductor layer; forming a mask layer through forming an opening at a portion of the mask material layer corresponding to the portion of the compound semiconductor layer where the defect exists; and etching the compound semiconductor layer for removing the portion of the compound semiconductor layer where the defect exists through the opening of the mask layer to form the defect-removed portion.