To provide a bedsore preventing mattress capable of contributing to a countermeasure to bedsore particularly at home.

This bedsore preventing mattress 1 is used on a mattress 2 used in a Japanese room. This mattress 1 is held on the mattress 2 by a non-slip member 5 provided on the revere side so as not to be shifted. In this mattress 1, a low-resilient soft material 3 of 30-70 mm thick having an apparent density of 10-100 kg/m3 and a compression hardness of 10-400 N is used as stuffing. The soft material 3 can be covered with a surface cloth 4 that is a stretchable waterproof sheet material without looseness to prevent the intrusion of external moisture or dirt to the soft material 3.