The invention discloses an air bag cuff and an automatic blood pressure measuring device. The air bag cuff comprises an inner ring air bag section, an outer ring air bag section and a dragging section. The overall shape of the air bag cuff is a sector ring. One or two or more air bags are installed in the air bag cuff. Each air bag is installed in an air bag connecting sleeve and located at the position corresponding to the position of the inner ring air bag section and the position of the outer ring air bag section. A supporting keel is arranged on the air bag buff. The supporting keel is arranged in a keel connecting sleeve. For the inner ring air bag section, under the condition that only one air bag is installed, the width of the supporting keel is basically equal to that of the air bag, and under the condition that two or more air bags are installed, the width of the supporting keel is basically equal to that of the air bag close to the long arc edge of the air bag cuff. In addition, the width of the portion, corresponding to at least most of the outer ring air bag section and the dragging section, of the supporting keel is reduced to about one third that of the outer ring air bag section. According to the air bag cuff and the automatic blood pressure measuring device, the one-way pressure exerted on a measured limb can be remarkably reduced, and the measurement precision of the automatic blood pressure measuring device is improved.
