Aspergillus oryzae secretes large amount of hydrolytic enzymes, while does not produce any toxins. Therefore, it has been used for manufacturing Japanese traditional foods such as alcohol (sake), soy sauce (shoyu), and soy paste (miso). A. oryzae is the filamentous fungus that has organelles in the cell, and thus it is considered appropriate for heterologous expression of genes derived from plants and animals, etc. Using such attractive characteristics of this fungus, we have been challenging the production of valuable compounds such as lipids and secondary metabolites useful as source materials of pharmaceutical agents etc. via genetic engineering.