One of the central issues for information extraction (IE) systems is the cost of customization from one scenario to another. Research on the automated acquisition of patterns is important for portability and scalability. This paper explores the automatic extraction of patterns in Japanese from unannotated text. We introduce two modules of our system, the pattern extraction module and the information extraction module, both of which use structural patterns. The performance of the whole system is measured in a MUC-style evaluation.