The power storage device comprises a plurality of cells (10), an exhaust passage (S1) and a sealing plate (20). The plural cells is aligned in a first direction (x), each of the cells includes a gas discharging valve (13) for discharging a gas generated in the cell, each of the gas discharging valves is provided on a first side in a second direction (z) of the cell, and the second direction is orthogonal to the first direction. The exhaust passage is configured to discharge the gas discharged from each of the gas discharging valves, extends in the first direction, and has an opening at a first end in the first direction. The sealing plate is provided at a second end of the exhaust passage in the first direction, includes plural recesses (22) on a surface on the exhaust passage side of the sealing plate, and made of a resin.