Disclosed are a composition for controlling the crystallization rate of a polyolefin-based resin, the composition comprising (A) an amide-based compound which is a substituted or unsubstituted cyclohexylamide of 1,2,3-propanetricarboxylic acid or 1,2,3,4-butanetetracarboxylic acid and (B) a fatty acid metal salt, wherein the component (A):component (B) weight ratio is from 100:0 to 30:70; a method for controlling the crystallization rate of a polyolefin-based resin, comprising incorporating the composition into the polyolefin-based resin to obtain a polyolefin-based resin composition and molding the resin composition; molded products obtained by the method; and the like.