Provided are a polychloroprene latex giving a rubber-asphalt composition superior in low-temperature stability and film-forming property on the material to be coated, a rubber-asphalt composition and a utilization method thereof, a sheet, and a waterproof coating film. The rubber-asphalt composition includes a major agent containing 10 to 40 mass % of the anionic polychloroprene latex comprising potassium ions in an amount of 0.7 to 1.5 parts by mass and sodium ions in an amount of controlled to be 0.2 part by mass or less with respect to 100 parts by mass of the solid matter and 60 to 90 mass % of an anionic asphalt emulsion; and a coagulating agent of an aqueous solution containing a polyvalent metal salt as the principal component.