To provide a resin composition having excellent low linear expansibility, impact resistance and heat resistance and to provide a rain gutter using the resin composition.

The polyvinyl chloride-based resin composition comprises 90-50 wt.% of a vinyl chloride resin (component a) composed of a vinyl chloride monomer and prepared by carrying out graft polymerization on a saturated elastic body, 10-50 wt.% of a resin (component b) obtained by conducting graft polymerization of at least a two-component monomer of -methylstyrene and acrylonitrile on polybutadiene and 20-60 pts.wt. of wollastonite (component c).