To provide an air-filled cushioning material, which allows small cells to swell sufficiently and keeps folds beautiful when the cushioning material is formed into a solid shape.

On the air-filled cushioning material 1, a plurality of small cells 2, which can be filled with air, are formed by gluing together necessary spots on overlapping flexible sheets 1a, 1b. The sheet 1a is flat, and the sheet 1b has the premolded air-filled cushioning material of shapes of swelled small cells 2 at the positions where the small cells 2 are to be shaped. This eliminates the problem that the small cells 2 cannot swell sufficiently when the cushioning material 1 is formed with the sheet 1b kept folded. Thus the small cells 2 made of the sheet 1b can be swelled enough into the shape as premolded.