A battery module has a battery stack that includes a plurality of prismatic batteries and an inter-battery separator disposed between every two of the prismatic batteries adjacent to each other in an X direction along which the plurality of prismatic batteries is stacked. The inter-battery separator includes: a middle member having a plate shape; a first side plate-shaped member disposed on a first side of the middle member in the X direction and made of a material that is superior in thermal insulation to the middle member; and a second side plate-shaped member disposed on a second side of the middle member in the X direction and made of a material that is superior in thermal insulation to the middle member.