With the aim to utilize pine wood(Pinus densiflora Sieb. et Zucc.) as an interior building materials, such as flooring material, monoethylene glycol(MEG) resin solution was impregnated into greenwood. Specimens of three different qualities, that is, normal wood, resinous wood and compression wood, were prepared. Distribution of resin element(phosphorus) in MEG resin solution-impregnated woods and preservative effectiveness against brown rot fungi(Tyromyces palustris and Serpula lacrymans) of these woods were investigated. The results were as follows: 1. The concentration of phosphorus into cell walls of resinous wood and compression wood was lower compared to that of normal wood. This shows that the quality of wood has an influence on the penetration of MEG resin solution into the wood. It was shown from a leaching test that MEG resin could be leached out easily from the cell walls. 2. The resinous wood and compression wood, even without MEG resin solution impregnation had high decay resistance. For normal wood, significant improvement of preservative effectiveness was observed after impregnation of MEG resin solution. It was shown that MEG resin was leached out from the woods after leaching test, resulting in the reduction of preservative effectiveness. From this result, suitability of MEG resin solution-impregnated woods as an interior materials was recognized.