By using a small number of needles and contact terminals at burn-in, electric contact check is performed between each needle and each terminal provided in each semiconductor chip, and thereby the yield of assembled products can be improved. A packaging structure in which, for example, a volatile memory chip and a nonvolatile memory chip are formed is assembled in accordance with a production scheme in which burn-in of each memory chip is performed while still under the state of a semiconductor wafer, and by forming the packaged structure using the good volatile memory chip subjected to burn-in and likewise, also, the nonvolatile memory chip. At this burn-in, contact check is performed by bringing a needle, provided in a burn-in board, into contact with, for example, six test-only signal terminals of a test circuit formed on each semiconductor chip.