The invention relates to an autonomous bed intended for patients with reduced mobility and particularly for tetraplegic and paraplegic persons, which is height adjustable and can switch between a horizontal position as a bed for accommodating the patient when he or she is lying down, and a stepped position as a chair. The bed incorporates transporting mats (12) for supporting the patient, which move in a direction transverse to supports (4, 5, 8), each in its own direction of movement: towards the outside of the bed, to move the patient from the bed to a bed or a wheelchair, for example and towards the inside of the bed, to accommodate the patient thereon. The longitudinal or transverse orientation of the bed can be changed with respect to the frame, permitting the patient to be able to perform his or her physiological necessities of evacuation by means of the stretcher in a seated position.