(i) A material is developed which modifies the rigidity, tensile elongation at break and impact resistance of resins such as a polypropylene resin when used as a modifier. The invention relates to an ethylene type ternary copolymer (A) comprising (i) an ethylene, propylene or 1-butene and a higher α-olefin having 6 to 20 carbon atoms, wherein the content of ethylene is 70 to 89 mol %, the content of propylene or 1-butene is 10 to 22 mol % and the content of a higher α-olefin having 6 to 20 carbon atoms is 1 to 11 mol % and the molar ratio of the higher-olefin having 6 to 20 carbon atoms to the structural units except for ethylene (either propylene or 1-butene and the higher α-olefin having 6 to 20 carbon atoms) is 1/10 to 5/10 and the ethylene type ternary copolymer has a density of 0.857 to 0.885 g/cm3. The invention also relates to (ii) a propylene type resin composition comprising a propylene type polymer (B), the ethylene type ternary copolymer (A) and an inorganic filler (C).