To provide a packing cushioning material wherewith a packing operation can be performed quickly without requiring a large storage space and in addition the cushioning material is easily reusable.

The packing cushioning material comprises a thin synthetic resin sheet material 10, which comprises first, second and third sides (11, 21, 31) and first and second linear folds (41, 51). A plurality of cushioning sections 61 are formed on the first, second and third sides (11, 21, 31), a locking recess 71 is provided on one of opposite sides (13, 23) of the first and second sides (11, 21), and a locking protrusion 81 is provided on the other. The first and second sides (11, 21) are folded at the right angle toward the third side 31 via the first and second linear folds (41, 51), and this state can be kept by fitting the locking protrusion 81 into the locking recess 71.