Manuals and procedure manuals for companies, etc. have attracted attention in the 2007 and 2012 issues, where there was concern that the labor force would decrease due to the mass retirement of baby boomers and the succession of technology and know-how in the companies would be disrupted. Many companies were attracting attention to make manuals. Many charts are used in the railway vehicle maintenance manual that we focused on. It has been clarified that the use of charts leads to motivation and promotion of understanding for readers, and it is considered that it has a role of effectively inheriting tacit knowledge. The purpose of this paper is to clarify the relation between ambiguous sentences including tacit knowledge, which is the key to technology succession, and figures that complement them. As a result of the analysis, it was found that the words on which the ambiguity was based were supplemented by charts and resolved for the sentences that the engineer read only the sentences and judged to be ambiguous. In addition, the characteristics were clarified by comparing the ambiguous sentences complemented by figures and tables with the ambiguous sentences that were not complemented.