The 3-tier folding sponge mattress, which is a modern reinterpretation of Japanese tatami minimalism, is a product optimized for the lifestyle of Korean consumers. The combination of high-density elastic sponge and breathable natural material cap gently supports the tired body and maintains it without deformation for more than 3 years through special compression processing technology. It is available in 5cm/9cm thickness and 90x200~150x200cm, a total of 6 sizes, and can be applied to all spaces such as studio apartments, officetels, and houses. It is characterized by a subway book bag size that can be folded and stored according to the season. It is designed to disperse weight of medium to high intensity to suit Korean tastes, taking into account spinal health, and is coated with a smart moisture-proof coating to maintain comfort even during the rainy season in summer. The patented folding structure can be used directly on the floor without a bed frame, and can be used for a variety of purposes, from a study bed for teenagers to temporary bedding for guests