In-vehicle electric storage device

An in-vehicle electric storage device includes: a battery block 100a, b including a metal casing and battery cells 140; a control unit 900 including a metal cabinet and a circuit board 950 on which an electronic component is mounted, the control unit 900 being on a top side of the battery block 100a, b and monitoring a physical state of the battery cells 140; wherein the cabinet includes a case having a bottom plate and an open top surface and a cover closing the open top surface, the case has an internal boss 932a protrudes toward inside of the case from a top side of the bottom plate and an external boss 932b protrudes toward outside the case from a bottom side of the bottom plate 930B, the circuit board 950 is on a top side of the internal boss 932a, and a top side of the casing is provided with a depressed portion in which the external boss 932b is accommodated.