An individual self-contained breathing apparatuses of closed cycle is proposed, including an air system, including a compensatory cylinder with compressed gas, a reducer and a manometer; a gas analyzing system; a regenerative device including reactors with cartridges with oxygen regenerating agent; a breathing circuit including a face mask, a space under the face mask, a breathing bag, a valve for releasing pressure in the breathing circuit; connecting air ducts for connecting the breathing circuit to the regenerative system and the air system, whereas all components are positioned in monoblock housing. The apparatus includes no supply of the breathing mixture. The apparatus can be used for recreational diving, technical diving, professional diving or rescue purposes.