Provided is a lithium titanate powder for an electrode of an energy storage device, wherein the lithium titanate powder includes Li4Ti5O12 as a main component and has a specific surface area of 5 to 50 m2/g, a total-fine pore volume of the lithium titanate powder is 0.03 to 0.5 ml/g and the lithium titanate powder includes a phosphorus atom in an amount of 0.03 to 1% by mass, an active material containing the lithium titanate powder, an electrode sheet containing the active material, and an energy storage device using the electrode sheet.