PURPOSE: To provide a fluorinated elastomer excellent, for example, in heat resistance and gas barrier properties, by specifying the weight ratios and the number-average molecular weights of the vinylidene fluoride unit and the hexafluoropropylene unit which are the constituent components.

CONSTITUTION: The title fluorinated elastomer is composed of 69W72.5wt.% vinylidene fluoride unit and 31W27.5wt.% hexafluoropropylene unit, and has a number-average molecular weight of 2×104W40×104. This elastomer is produced by, for example, dispersing an active organic solvent in which the vinylidene fluoride unit and the hexafluoropropylene unit are dissolved in required amounts into an aqueous medium, adding necessary additives such as a stabilizer, a polymerization initiator and a chain transfer agent thereto, and carrying out the suspension polymerization. The produced elastomer can be suitable used for sealing materials of packings, gaskets, diaphragms, etc.