An electricity storage device includes: a first battery stack (15) including a plurality of cells that are aligned in a first direction; a second battery stack (11 to 14) including a plurality of cells that are aligned in a second direction different from the first direction, the second battery stack being placed under the first battery stack; and a duct for coolant. The duct is disposed along the first battery stack and is positioned between the first battery stack and the second battery stack.