A carboxylic acid-modified nitrile copolymer latex is provided. The copolymer latex comprises a carboxylic acid-modified nitrile copolymer of an unsaturated monomer having at least one crosslinkable functional group selected from vinyl and epoxy groups. The use of the copolymer latex enables the production of a molded article that does not undergo long stirring and maturation, causes no allergic reactions due to the absence of sulfur and a vulcanization accelerator, has good oil resistance and high mechanical strength, and produces a soft feeling. Further provided is a latex composition for dip forming comprising the copolymer latex, and an article produced from the latex composition by dip forming.