To provide a resin composition reducing a load on the environment and developing suitable strength.

The composition comprises one or two or more kinds of first polymers selected from a polyphenolic material obtained by mixing an acid with a lignocellulosic material containing a phenol derivative added thereto, one or two or more kinds of second polymers having any one or two or more kinds of an oxygen atom, a nitrogen atom and a hydrogen atom in the main chain or the side chain so that a matrix comprising the first polymers and the second polymers develops higher strength than that of a matrix solely comprising each polymer. According to the composition, the high strength can be developed by an interaction of the first polymers with the second polymers.