Provided are a rubber composition that gives a vulcanizate superior in heat resistance and a vulcanizate and a molded article thereof. A rubber composition, comprising a rubber component consisting of a chloroprene rubber: 50 to 90 mass % and an elastomer: 10 to 50 mass % in a total amount of 100 parts by mass, a zinc powder having an arithmetic mean particle diameter, as determined by the method specified by JIS Z8901, of 3 to 10 µm in an amount of 3 to 20 parts by mass, and a magnesium oxide having a BET specific surface area, as determined by the one-point method specified by JIS Z8830, of 20 to 150 m 2 /g in an amount of 4 to 16 parts by mass. A vulcanizate and a molded article obtained by molding and vulcanization of the rubber composition.