Electricity storage device

To provide an electricity storage device which has a good balance between ease of battery module exchange and excellent vibration resistance/impact resistance. An electricity storage device (1300) of the present invention comprises: a bottom plate (1210) which has a plurality of lower guide members; a top plate (1220) which is arranged above the bottom plate (1210) and has a plurality of upper guide members that face the lower guide members; a first lateral plate (1230) and a second lateral plate (1240) which face each other and are arranged between the bottom plate (1210) and the top plate (1220); a back plate which is arranged between the first lateral plate (1230) and the second lateral plate (1240) and has a plurality of connectors; a battery module (1000) which is inserted between the lower guide members and the upper guide members and has a connector that is fitted with a connector of the back plate; and a pressing plate (1260) which is arranged between the first lateral plate (1230) and the second lateral plate (1240) and is affixed to the first lateral plate (1230) and the second lateral plate (1240), and which presses the battery module (1000).