The objective of the invention is to provide an agent for increasing a plant functional component content, which is capable of increasing a content of the plant functional component by being adequately sprayed to the plant or injected into the soil without using stress cultivation conditions or plants with high content of functional component, and a method for manufacturing the same. An agent for increasing a plant functional component content comprising a fatty acid metabolite obtainable by a metabolism of a fatty acid with 4-30 carbon atoms by proteobacteria under a dissolved oxygen concentration of 0.1-8 mg/L, and a method for manufacturing an agent for increasing a plant functional component content comprising a fatty acid metabolite, comprising a step for a fatty acid metabolism wherein a fatty acid with 4-30 carbon atoms is subjected to a proteobacterial metabolization under a dissolved oxygen concentration of 0.1-8 mg/L.
