The present invention provides a resin composition containing a filler poor in affinity for fluororesins as uniformly dispersed therein and a method of producing such resin composition and, further, a resin composition containing, as fillers, a nucleating agent for foaming and suited for producing foamed moldings with fine foam cells uniformly distributed therein and a method of producing such resin composition as well as a foamed molding formed from either of such resin compositions. The present invention is related to a resin composition comprising a fluororesin (A) and a filler (X) low in affinity for said fluororesin (A), wherein the filler (X) has a d99 value of not more than 15 μm.