To provide a reuse method for a matrix which can release easily between the matrix and an electrocast product, without dissolving the matrix with solvent and taking out the electrocast product or without cutting off the matrix and taking out the electrocast product, when a cylindrical seamless electrocast product, such as a roll is manufactured.
The process is as following. A sealed container is made of a base material. After the inside of the sealed container is filled with a fluid, the sealed container is pressurized by a pressurizing pump, so the sealed container is expanded. At the expanded state, the base material is finished into a necessary shape and dimension by a lathe or the like. The matrix 7 is manufactured. After electrocasting, the releasing operation between the matrix and the electrocast product 8 can be easily performed by generating a gap between the matrix and the electrocast product by reducing the inner fluid pressure.