A buffer member, comprising: a resin sheet (81, 82) welded in a bag-like shape; and a medium sealed in the resin sheet (81, 82), wherein the resin sheet (81, 82) includes a plurality of buffer areas each having a shape extending longitudinally in a first direction and arranged adjacent to each other in a second direction orthogonal to the first direction, each buffer area of the plurality of buffer areas includes a first buffer chamber having a shape extending in the first direction, a second buffer chamber having a shape extending in the first direction and formed at a position separated from the first buffer chamber in the first direction, and a connecting flow passage connecting the first buffer chamber and the second buffer chamber, a length of the connecting flow passage in the second direction is smaller than a length of the first buffer chamber and a length of the second buffer chamber in the second direction, and the connecting flow passage of one buffer area of the plurality of buffer areas and the connecting flow passage of an adjacent buffer area adjacent to the one buffer area of the plurality of buffer areas are separated from each other in the second direction, characterised in that the connecting flow passage includes a first passage formed in a first direction, a second passage that bends from the first passage and that is formed in a second direction, and a third passage that bends from the second passage and that is formed in the first direction, such that the connecting flow passage directs the medium flowing into the connecting flow passage from one of the first buffer chamber and the second buffer chamber along the first direction to bend in a direction intersecting the first direction, while redirecting the medium flowing out of the connecting flow passage and into the other buffer chamber of the first buffer chamber and the second buffer chamber to bend in the first direction again. a resin sheet (81, 82) welded in a bag-like shape; and a medium sealed in the resin sheet (81, 82), wherein the resin sheet (81, 82) includes a plurality of buffer areas each having a shape extending longitudinally in a first direction and arranged adjacent to each other in a second direction orthogonal to the first direction, each buffer area of the plurality of buffer areas includes a first buffer chamber having a shape extending in the first direction, a second buffer chamber having a shape extending in the first direction and formed at a position separated from the first buffer chamber in the first direction, and a connecting flow passage connecting the first buffer chamber and the second buffer chamber, a length of the connecting flow passage in the second direction is smaller than a length of the first buffer chamber and a length of the second buffer chamber in the second direction, and the connecting flow passage of one buffer area of the plurality of buffer areas and the connecting flow passage of an adjacent buffer area adjacent to the one buffer area of the plurality of buffer areas are separated from each other in the second direction, characterised in that the connecting flow passage includes a first passage formed in a first direction, a second passage that bends from the first passage and that is formed in a second direction, and a third passage that bends from the second passage and that is formed in the first direction, such that the connecting flow passage directs the medium flowing into the connecting flow passage from one of the first buffer chamber and the second buffer chamber along the first direction to bend in a direction intersecting the first direction, while redirecting the medium flowing out of the connecting flow passage and into the other buffer chamber of the first buffer chamber and the second buffer chamber to bend in the first direction again.