A packaging buffer material includes a pair of outer sidewalls having concave grooves in a length direction, and bottom wall having a concave groove in the length direction, and stoppers, preventing a packing object from being displaced, attached between the sidewalls. If external pressure is applied to the packaging buffer material, the outer sidewalls and concave groove bottoms are deformed. However, because of narrow widths of the concave grooves, the outer sidewalls are not entirely deformed but only the concave grooves are deformed. Due to this, a space can be kept between the sidewalls even if high external pressure is applied to the packaging buffer material.