The present invention relates to a means for retaining stably a posture of a subject or a patient during a medical practice, namely, a medical posture retainer having a mat 1 and a core member. The mat 1 is composed of an airtight bag 2 and a cushion layer 3. The airtight bag 2 is a cover of the mat 1 supporting the human body and retaining the posture. The airtight bag 2 has a gas barrier property, and an exhaust valve for deflation is attached to the airtight bag 2. The cushion layer 3 is formed of strata of particles P filled in the airtight bag 2. The core member includes a plate-like support 4 that is attached to a (inner or outer) side face of the airtight bag 2 to keep a certain rise height of the airtight bag 2, and a stopper 6 that is attached to the upper face and the lower face of the airtight bag 2 so as to restrict the rise height of the airtight bag 2. The core member is attached to the airtight bag 2 before deflation of the airtight bag 2 so as to impart a shape necessary for receiving a specific part of a human body.
