To provide a warmth retaining bed using bamboo ash powder which is less prone to be damaged during a long-time use and can be washed in the warmth retaining bed configured by sealing bamboo ash powder in a bag-like body.

In the warmth retaining bed using the bamboo ash powder formed approximately planar and configured by sealing bamboo ash powder 2 into a gas-permeable bag-like body 1 and covering the bag-like body 1 with an exterior body 3, the bag-like body 1 is sealed in a storage bag 4 formed a little larger than the bag-like body 1 for free inside movement.