A system for assisting respiration which includes a flat, belt-shaped, tube made of rubber, and having a valve for introducing air. The flat tube has an outer side comprising a layer of a rubber sheet having a high modulus of elasticity and an inner side comprising a layer of a rubber sheet having a low modulus of elasticity, and is attachable to a part of a lower breast to an upper abdomen portion of a patient for intermittently pressing the part of the lower breast to the upper abdomen portion of the patient responsive to air being introduced into the flat tube. A belt, having a same width as that of the flat tube and a length longer than that of the flat tube, is laminated to the flat tube at the outside of the flat tube, and may have sheet fasteners at both ends thereof. A flow sensor detects inspiration and expiration of a patient, a compressor supplies compressed air to the flat tube during a period of inspiration of the patient, a pressure regulator regulates a pressure of the compressed air supplied to the flat tube, a valve is provided for increasing the pressure of the compressed air supplied to the flat tube, and a release valve is provided for releasing pressure in the flat tube at an early time in a period of expiration of the patient. A switchover valve may be provided for causing the compressor to supply compressed air to the flat tube during the period of expiration and for causing the release valve to release pressure in the flat tube at the start of inspiration.