To provide a resin composition capable of providing the resin composition having a good dispersibility of a biodegradable resin.

This method for producing the resin composition is provided by comprising a first kneading process for producing a resin composition precursor by kneading (A) the biodegradable resin and (B) a compound having a reactivity with the biodegradable resin (A), and a second kneading process of kneading the resin composition precursor and (C) a polyolefin-based resin.