PURPOSE: To foamably mold foamable polyurethane resin in a spherical shape of arbitrary size by dropping liquidlike polyurethane resin at the initiation of reaction in powder particles having no reactivity with the polyurethane resin with a bulk specific weight smaller than the final bulk specific weight of foamed foamable polyurethane resin.

CONSTITUTION: Liquidlike polyurethane resin 1a is mixed at a suitable mixture ratio by a conventional mixer, and dropped from the injection port 10 of an injection nozzle 11. The injection port 10 is spirally turned to be moved when the liquidlike polyurethane resin 1a is dropped so that the polyuethane resin 1a is not dropped at the same position. When the specific weight of powder particle 2 is smaller by approx. 0.1 - 0.5 than the final bulk specific weight of the foamed polyurethane resin, its dropping speed can be easily controlled. When the liquidlike polyurethane resin 1a is dropped thereinto while a vessel 13 filled with the powder particle 2 is being vibrated by a vibrator 14, the dropping speed of the liquidlike polyurethane resin 1a dropped into the powder particle 2 is forcibly increased.