In this power storage apparatus, a bag-shaped separator is provided with: a first welded part that is present along a first end edge of the bag-shaped separator and that is obtained by welding marginsof two separator members to each other; and a first unwelded part that is positioned closer to the first end edge than the first welded part and at which the two separator members are not welded to each other. The bag-shaped separator is provided with: a second welded part that is present along a second end edge and that is obtained by welding margins of the two separator members to each other; and a second unwelded part that is positioned closer to the second end edge than the second welded part and at which the two separator members are not welded to each other. In the power storage apparatus, the relationship that the width of the first unwelded part is larger than the width of the second unwelded part is satisfied.