A power storage device comprising: plural cells aligned in a first direction, each of the cells including a gas discharging valve for discharging a gas generated in the cell, each of the gas discharging valves being provided on a first side in a second direction of the cell, and the second direction being orthogonal to the first direction; an exhaust passage configured to discharge the gas discharged from each of the gas discharging valves of the plural cells, the exhaust passage extending in the first direction, and the exhaust passage having an opening at a first end in the first direction; a sealing plate provided at a second end of the exhaust passage in the first direction, the sealing plate being made of a resin; and a cover member disposed separately from the cell on the first side in the second direction of the cell, the cover member defining a wall of the exhaust passage on the first side in the second direction of the exhaust passage, the cover member facing the gas discharging valve with interval in the second direction of the gas discharging valve, characterised in that the sealing plate includes plural recesses on a surface on the exhaust passage side of the sealing plate; the cover member is made of a metal and in that the power storage device comprises plural partitioning plates, each of the partitioning plates being provided between the cells in the first direction, each of the partitioning plates includes a joining section projected to the first side in the second direction of the cell, the joining sections extending in two rows in the first direction, the joining sections defining a sidewall of the exhaust passage, and the gas discharging valve being positioned between the two rows of the joining sections. plural cells aligned in a first direction, each of the cells including a gas discharging valve for discharging a gas generated in the cell, each of the gas discharging valves being provided on a first side in a second direction of the cell, and the second direction being orthogonal to the first direction; an exhaust passage configured to discharge the gas discharged from each of the gas discharging valves of the plural cells, the exhaust passage extending in the first direction, and the exhaust passage having an opening at a first end in the first direction; a sealing plate provided at a second end of the exhaust passage in the first direction, the sealing plate being made of a resin; and a cover member disposed separately from the cell on the first side in the second direction of the cell, the cover member defining a wall of the exhaust passage on the first side in the second direction of the exhaust passage, the cover member facing the gas discharging valve with interval in the second direction of the gas discharging valve, characterised in that the sealing plate includes plural recesses on a surface on the exhaust passage side of the sealing plate; the cover member is made of a metal and in that the power storage device comprises plural partitioning plates, each of the partitioning plates being provided between the cells in the first direction, each of the partitioning plates includes a joining section projected to the first side in the second direction of the cell, the joining sections extending in two rows in the first direction, the joining sections defining a sidewall of the exhaust passage, and the gas discharging valve being positioned between the two rows of the joining sections.