A sphygmomanometer cuff (10A) having an air bag (12) arranged within an outer bag (11), from which a tube (13) attached to the air bag (12) is extended outward, is provided. The outer bag (11) is provided with an opening portion (15) for replacing the air bag, and an anti-rotating member (20) for preventing rotation of the air bag (12) within the outer bag (11) is provided at a tube attaching portion (17) of the air bag (12) or at the vicinity thereof. The tube (13) of the air bag (12) is drawn out of the outer bag (11) through the opening portion (15). This structure allows replacement of the air bag (12) and, in addition, prevents any inconvenience such as winding of the air bag (12) within the outer bag and the like.