Abstract: In order to allow differentiation induction of cancer cells into normal cells, the present invention provides an activator of mitochondria containing a component expected to have an epigenetic action, or provides a cell differentiation inducer having a novel composition that has an action to activate mitochondria. The activator of mitochondria contains, as an effective component, 0.03 to 300 ?g/mL of a single component of kaempferol, or a mixture component of kaempferol and glycerol. These agents can promote DNA methylation, activate resting genes in cancer cells such as leukemia cells to promote their normal cell division according to the normal cell cycle, and activate mitochondrial functions, to thereby allow continuous differentiation induction into normal cells without arresting the cell differentiation.