The cotton fabric armour for lower class soldiers can be found from the historical records of the mid-Joseon Korea. And the records show that the form and the structure of the armour was modified in the late 19th century in order to provide better protection from gunshots for the soldiers in the midst of the invasions from the West. This is a survey and research of the only artifact of the cotton fabric armour remaining in Korea - for its form, dimensions, and design. Using the historical records as reference, we can confirm the structure and characteristics of the cotton fabric armour of the Joseon period. This cotton fabric armour, preserved in National Museum of Korea, is a vest-type armour made of 30 layers of cotton. On the right shoulder, there is a button for tying knots and strings were tied under both armpits. On the surface of the cotton fabric armour there were some characters and patterns stamped in black. Presently, this artifact in Korea is the only specimen relic of its sort, but there are some other related relics in foreign countries including helmets and belts. Continuous researches would help extend the scope of armour study beyond the traditional researches that only focuses on the armours of the officials, thus helping us to understand the military costumes in traditional Korea.