A production process for a viscosity-stabilizer-containing natural rubber comprising a step of adding a viscosity stabilizer liquid diluted with a solvent to a natural rubber, and a viscosity-stabilizer-containing natural rubber latex to which added is a viscosity stabilizer dissolved in an aliphatic chain compound, and a viscosity-stabilizer-containing natural rubber obtained by adding a viscosity stabilizer liquid diluted with a solvent to a natural rubber after it was coagulated.