The purpose of this paper is to investigate Hayashi Shojuro's seldom explored translation, "Mokuba no Sho" (The Book of Wooden Horse) and its publishing history, and to determine its meaning for the modern physical education in Japan. "Mokuba no Sho" is more of a book on horse vaulting than simply a book on horse riding because of its description of the five kinds of exercises from the back of the horse and twelve exercises from the side of horse. The contents of this book are in complete agreement and comspicious similarity to the French Army's textbook on gymnastics instruction "Ministere de la guerre (1st Ed. 1847) :Instruction pour l'enseignement de la gymnastique". Therefore, it is unquestionable that "Mokuba no Sho" was translated from it. Hayashi Shojuro (1824-1896, formerly a professer of French at Kaiseisho, National Academic Institute) was one of the most famous scholars at the end age of the Edo period.From December 1866 to the early spring of 1868, he also held an additional post as the official French translator for the Japanese Army in the cavalry, artillery and infantry divisions. This was necessary because the Tokugawa Shogunate employed a party of military advisers from France, whose leader was Captain Chanoine. Even though the translation of "Mokuba no Sho" is not clearly dated, it can be presumed that it was prepared in 1867 because of Hayashi's occupation as a translator for the party of French Military advisers and his subsequent military service for the Tokugawa Shogunate in the Boshin civil war from early 1868. It is well known fact that the party of French military adviser seriously considered basic gymnastics as necessary for soldier training, and taught Japanese soldiers how to do gymnastics (rentaiho). Furthermore, in the memorial presented to shogunate in 1867 (The Chanoine Memorial), it is clearly written that the party had brought with them a fully illustrated book on gymnastics. Initially Hayashi Shojuro read the book as the official translator. He took particular notice of the section on horse vaulting as training for the cavalry and subsequently translated it into Japanese. The historical meanings of this book for physical education in modern Japan are as follows : 1. It is the oldest book dealing with the physical education of the west. 2. This is a memorable book in the history of Japanese physical education because it was the first academic study based on an original foreign text, "Ministere de lA guerre (1st Ed.1847) : Instruction pour l'enseignement de la gymnastique." 3. During the first half of the Meiji period French gymnastics were for the most part by the military. For example, "Taiso Kyohan" (Textbook of Gymnastics) was written by the military, modeled after the French version. It was later applied to physical education in Japan's middle school System. "Mokuba no Sho" was the first book in the history on French gymnastics in the Meiji period. 4. This is the first book in which the scientific term of the study of physical education as "shintai undo gaku" (science of physical movement) was used. 5. This book shows us that the apparatus of gymnastics in Japan was derived from the French military gymnastics, especially horse vaulting for the training of the cavalry. Above all, "Mokuba no Sho" is memorable as the book which introduced modern European physical education to Japan.