The purpose of this paper is to examine the mathematical treatise Kujutsu Shinsho written by Heinouchi Masaomi, the master of carpenters in Edo period. The basic tools used in the book are right triangles and similarities between them. The materials are concerned with carpenters' daily works. Almost all problems are elementary but the problems about extracting square and cubic root are still very interesting for us, for he describes the procedure of drawing the square or cubic root for a given positive integer.
