The present invention provides: a novel cellular life span extending agent, particularly an agent for extending the life span of an endothelial cell, which comprises an extract derived from a plant belonging to the genus Cinnamomum; and a telomerase activator.本發明提供一種包含源自肉桂(Cinnamomum)屬植物之萃取物的新穎細胞壽命延長劑、尤其是血管內皮細胞壽命延長劑,及端粒酶活化劑。