PROBLEM TO BE SOLVED: To provide a functional compost utilizing a bacterium having a pathogenesis reducing effect on all of fusarium wilt, damping-off and root rot of spinach.SOLUTION: A bacterium KS22 strain that grows in a food waste as a main nutrient source, does not have pathogenicity to spinach but has antagonism to pathogen of fusarium wilt, pathogen of damping-off and pathogen of root rot of spinach and belongs to the genus Bacillus is subjected to liquid culture. The liquid culture is mixed with a solid medium containing a plant-based full ripeness compost and the bacterium KS22 strain is acclimatized to produce compost.