PURPOSE: To impart a hot spring treating effect to the synthetic resin molding for bedding, etc., by incorporating or sticking hot spring treating materials, such as carbonate, earth metal salt of lrcarbonic acid, sodium bicarbonate, radon and radium, to the above-mentioned molding.

CONSTITUTION: The materials having the hot spring treating effect, for example, carbonates, such as sodium carbonate and calcium carbonate, sulfates, such as sodium sulfate, calcium sulfate and alum, and sulfur, radon, radium, etc., are incorporated or stuck alone or in combination of ≥2 kinds into the synthetic resin molding consisting of a polystyrene resin, etc. A method for mixing the above-mentioned materials into the resin, method for incorporating the materials into foamed beads, spraying method, dipping method, and color coating are properly adopted as the method therefor.