In an artificial photosynthesis module, a plurality of first electrode portions of a hydrogen generation electrode are disposed side by side with a gap, and each of a plurality of second electrode portions of an oxygen generation electrode is disposed at a gap between the first electrode portions of the hydrogen generation electrode as seen from the hydrogen generation electrode side with respect to the diaphragm. A first photocatalyst layer of at least one first electrode portion of the hydrogen generation electrode or a second photocatalyst layer of at least one of the second electrode portions of the oxygen generation electrode is tilted with respect to a flow direction of an electrolytic aqueous solution, or a projecting part is provided on a surface of the first photocatalyst layer of at least one first electrode portion of the hydrogen generation electrode or a surface of the second photocatalyst layer of at least one second electrode portion of the oxygen generation electrode.