A room temperature fast-curable saturated hydrocarbon polymer composition comprising (A) a saturated hydrocarbon polymer having at least one hydrolyzable silyl group and a Mn of 500 to 50,000, (B) a .beta.-dicarbonyl compound, and (C) an amino-bearing organic compound, wherein the .beta.-carbonyl group in component (B) is reactive with the amino group in component (C), is dramatically improved in fast-cure and deep-cure capabilities without sacrificing adhesion and electrical properties after water immersion.