The Bocho Syobukan Museum of the Japan Ground Self-Defense Force Camp in Yamaguchi holds the ceremonial military uniform of the 18th Prime Minister and Marshal General Terauchi Masatake. In order to reconstruct Terauchi’s ceremonial garment, we conducted an investigation of the documents and actual materials. As a result of the investigation, a label of Tokyo Mitsukoshi was discovered to be sewn inside the inner pocket of the upper garment.