Abstract: The power storage device includes a plurality of power storage stacks, a case, and a protective structure that protects a plurality of power storage cells from a load applied to the case in the vertical direction. The case has a bottom wall, a top wall, and a circumferential wall. The protective structure has a cross member, and a load transfer member located on the cross member. The load transfer member has at least one contact portion that is compressible and deformable in an orthogonal direction, and contacts a pair of power storage stacks adjacent to each other in the orthogonal direction when being in a compressed state.