PURPOSE: To obtain a vulcanized acrylic rubber of excellent properties in good workability within a short time, by copolymerizing an acrylate ester with an acetoacetate group-containing monomer and vulcanizing the copolymer by the addition of hexamethylenetetramine.

CONSTITUTION: 98W90wt% acrylate monomer (e.g., ethyl acrylate or n-butyl acrylate) is copolymerized with 2W10wt% acetoacetate group-containing monomer (allyl acetoacetate or methallyl acetoacetate). The obtained acrylic rubber is vulcanized at a temperature of about 150°C by the addition of a vulcanizing agent comprising hexamethylenetetramine to obtain the purpose vulcanized acrylic rubber. The vulcanizing agent comprising hexamethylenetetramine has a high rate of vulcanization and is effective in accelerating vulcanization even at room temperature and therefore, it is preferably used in a microencapsulated form.