In this paper we propose product line based component unification to reuse works required for component unification such as combined tests, WCET estimation, etc. and properties produced by component unification such as documents, binaries etc. We perform a case study of the personal destination screen with personal identification and find that component unification is worth to consider in product line engineering. Moreover, we present a sketch of an algorithm, which we expect to use in product line engineering tools, to exploit candidate components to be unified for strategic reuse along the product line with the feature model diagram of FORM product line engineering.