PROBLEM TO BE SOLVED: To provide an intestinal adjuvant containing Ganoderma lucidum spore.SOLUTION: Ganoderma lucidum spore shows an excellent intestinal adjuvanticity. Particularly, Ganoderma lucidum spore shows the growth action of cells included in intestinal Peyers patches, the growth action of helper T cell and/or B cell included in intestinal Peyers patches, and the production promoting action of interferon &gamma in intestinal Peyers patches. The intestinal adjuvant of the invention can be utilized as pharmaceuticals and quasi drugs or foods having safe and excellent intestinal adjuvanticity.