A logical formulation system functions to verify consistency of legal documents, and to eliminate inconsistent parts from a set of articles. We are studying legal document analysis methods, and in this paper we focus on how to deal with multiple sentences which constitute a paragraph of an article in a law. They need to be processed together because they are semantically dependent on each other. We analyzed National Pension Law of Japan and found that relations between sentences and their logical structures can be classified into four main types. We implemented a logical formulation system, which showed reasonable accuracy in dealing properly with paragraphs consisting of multiple sentences.