Contents adaptation is a technology which converts one content to another content used in various devices. Specially, synchronization of inter-media which are included in a document is needed. There are various proposals and solutions for synchronization of inter-media. In the paper, I present "TATS : Temporal Aggregate Tree Strategy" model, which is used for specifying the temporal relationship among media in series of time. In the TATS model, aggregate tree, a sort of a binary tree, is generated from the execution time of those media. Using this aggregate tree, I implemented the inter-media synchronizations.